<PAGE>
                                                                   EXHIBIT 10.23


                                     Lease


                                by and between


                              Boulder 38/TH/ LLC


                                      and


                             Genomica Corporation

                               December 30, 1999
<PAGE>

<TABLE>
<S>                                                                                                           <C>
ARTICLE I - REFERENCE DATA..................................................................................    1
   1.1   BASIC LEASE TERMS..................................................................................    1
         -----------------
   1.2   EXHIBITS...........................................................................................    3
         --------
ARTICLE II - PREMISES AND TERM..............................................................................    3
   2.1   PREMISES...........................................................................................    3
         --------
   2.2   APPURTENANT RIGHTS AND RESERVATIONS................................................................    3
         -----------------------------------
   2.3   TERM...............................................................................................    3
         ----
ARTICLE III - DELIVERY OF PREMISES; CONSTRUCTION............................................................    3
   3.1   INITIAL CONSTRUCTION...............................................................................    3
         --------------------
   3.2   DELIVERY OF POSSESION AND COMMENCEMENT DATE........................................................    4
         -------------------------------------------
   3.3   CONCLUSIVENESS OF LANDLORD'S PERFORMANCE...........................................................    4
         ----------------------------------------
   3.4   GENERAL PROVISIONS APPLICABLE TO CONSTRUCTION......................................................    4
         ---------------------------------------------
ARTICLE IV - RENT...........................................................................................    5
   4.1   BASE RENT..........................................................................................    5
         ---------
   4.2   ADDITIONAL RENT....................................................................................    6
         ---------------
   4.3   REAL PROPERTY TAXES................................................................................    7
         -------------------
   4.4   CAM EXPENSES.......................................................................................    7
         ------------
   4.5   PAYMENTS...........................................................................................    8
         --------
ARTICLE V - LANDLORD'S COVENANTS............................................................................    9
   5.1   LANDLORD'S COVENANTS DURING THE TERM...............................................................    9
         ------------------------------------
   5.2   INTERRUPTIONS......................................................................................   10
         -------------
ARTICLE VI - TENANT'S COVENANTS.............................................................................   10
   6.1   TENANT'S COVENANTS DURING THE TERM.................................................................   10
         ----------------------------------
ARTICLE VII - CASUALTY AND TAKING...........................................................................   16
   7.1   CASUALTY AND TAKING................................................................................   16
         -------------------
   7.2   RESERVATION OF AWARD...............................................................................   16
     ------------------------
ARTICLE VIII - RIGHTS OF MORTGAGEE..........................................................................   16
   8.1   SUBORDINATION......................................................................................   16
         -------------
   8.2   SUCCESSOR LANDLORD.................................................................................   17
         ------------------
   8.3   NO PREPAYMENT OR MODIFICATION, ETC.................................................................   18
         ----------------------------------
ARTICLE IX - DEFAULT........................................................................................   18
   9.1   EVENTS OF DEFAULT..................................................................................   18
         -----------------
   9.2   TENANT'S OBLIGATIONS AFTER TERMINATION.............................................................   19
         --------------------------------------
ARTICLE X - RIGHT OF RENEWAL; RIGHT OF FIRST NEGOTIATION....................................................   20
   10.1   RENEWAL OPTIONS...................................................................................   20
          ---------------
   10.2   RIGHT OF FIRST NEGOTIATION........................................................................   21
          --------------------------
ARTICLE XI - MISCELLANEOUS..................................................................................   21
   11.1   NOTICES FROM ONE PARTY TO THE OTHER...............................................................   21
          -----------------------------------
   11.2   BIND AND INURE....................................................................................   22
          --------------
   11.3   NO SURRENDER......................................................................................   22
          ------------
   11.4   NO WAIVER, ETC....................................................................................   22
          --------------
   11.5   NO ACCORD AND SATISFACTION........................................................................   22
          --------------------------
   11.6   CUMULATIVE REMEDIES...............................................................................   23
          -------------------
   11.7   LANDLORD'S RIGHT TO CURE..........................................................................   23
          ------------------------
</TABLE>
<PAGE>

<TABLE>
<S>                                                                                                           <C>
   11.8      ESTOPPEL CERTIFICATE...........................................................................   23
             --------------------
   11.9      WAIVER OF JURY TRIAL...........................................................................   24
             --------------------
   11.10     ACTS OF GOD....................................................................................   24
             -----------
   11.11     BROKERAGE......................................................................................   24
             ---------
   11.12     SUBMISSION NOT AN OFFER........................................................................   24
             -----------------------
   11.13     APPLICABLE LAW AND CONSTRUCTION................................................................   25
             -------------------------------
   11.14     SECURITY DEPOSIT...............................................................................   25
             ----------------
   11.15     SIGNS..........................................................................................   26
             -----
EXHIBIT A - PLAN OF PREMISES................................................................................  A-1
EXHIBIT B - WORK LETTER.....................................................................................  B-1
EXHIBIT C - IRREVOCABLE LETTER OF CREDIT....................................................................  C-1
</TABLE>
<PAGE>

                                   ARTICLE I
                                REFERENCE DATA

1.1  BASIC LEASE TERMS.

     Each reference in this Lease to any of the following subjects shall be
construed to incorporate the data stated for that subject in this Section 1.1:

LANDLORD:                                Boulder 38/th/ LLC, a Delaware limited
                                         liability company

LANDLORD'S NOTICE ADDRESS:               c/o Great Point Investors LLC 265
                                         Franklin Street, 18/th/ Floor Boston,
                                         MA 02110
                                         Attn: John H. Baxter

                                         with a copy to:
                                         Bancroft Capital Advisors, Inc.
                                         1112 Ocean Drive, Suite 300
                                         Manhattan Beach, CA
                                         Attn: Douglas J. McDonald

TENANT:                                  Genomica Corporation

TENANT'S NOTICE ADDRESS:                 1745 38/th/ Street
                                         Boulder, CO
                                         Attn: Dan Hudspeth

PREMISES:                                24,000 rentable square feet in the
                                         building commonly known as 1745 38/th/
                                         Street, Boulder, Colorado (the
                                         "Building"), which Premises are shown
                                         on the plan attached to this Lease as
                                         Exhibit A, together with the right, in
                                         ---------
                                         common with others, to use certain
                                         parking areas and other improvements
                                         related to the Building and the
                                         property known as 1715-1785 38/th/
                                         Street (the "Property")

RENTABLE FLOOR AREA OF PREMISES:         24,000 rentable square feet

COMMENCEMENT DATE:                       Substantial completion of Landlord's
                                         Work (as provided for in Section 3.1)
<PAGE>

BASE RENT COMMENCEMENT DATE:             One month after the Commencement Date

BUILDING RENTABLE AREA:                  55,645 rentable square feet

TENANT'S PRO RATA SHARE:                 43%

EXPIRATION DATE:                         Five years from the Rent Commencement
                                         Date

TERM:                                    Approximately five years and one month
                                         commencing on the Commencement Date and
                                         expiring on the Expiration Date

LEASE YEAR:                              The period of twelve full calendar
                                         months beginning with the first full
                                         calendar month of the Term, and each
                                         subsequent period of twelve full
                                         calendar months during the Term

ANNUAL BASE RENT:                        Lease Year 1    $366,000
                                         Lease Year 2    $376,980
                                         Lease Year 3    $388,290
                                         Lease Year 4    $399,939
                                         Lease Year 5    $411,937

SECURITY DEPOSIT:                        Irrevocable letter of credit in the
                                         following amounts:

                                         Lease Year 1    $350,000
                                         Lease Year 2    $315,000
                                         Lease Year 3    $270,000
                                         Lease Year 4    $215,000
                                         Lease Year 5    $170,000

                                         If the Tenant does not spend all of the
                                         Tenant Improvement Allowance, the
                                         Security Deposit shall be reduced by
                                         the amount not expended.

PERMITTED USES:                          General office purposes

TENANT IMPROVEMENT ALLOWANCE:            $216,000 ($9.00/RSF)

PARKING SPACES:                          80 unreserved spaces
                                         (3 spaces per 1,000 RSF)

BROKERS:                                 Dean Callan & Company, Frederick Ross
                                         Company and The Staubach Company
<PAGE>

1.2  EXHIBITS.

     The exhibits listed below in this section are incorporated in this Lease by
reference and are to be construed as part of this Lease:

     EXHIBIT A      Plan of Premises
     EXHIBIT B      Work Letter
     EXHIBIT C      Form of Letter of Credit

                                  ARTICLE II
                               PREMISES AND TERM

2.1  PREMISES.

     Landlord hereby leases to Tenant, and Tenant leases from Landlord the
Premises for the rents hereinafter reserved, and upon and subject to the terms
and conditions of this Lease.

2.2  APPURTENANT RIGHTS AND RESERVATIONS.

     Tenant shall have, as appurtenant to the Premises, the nonexclusive right
to use and to permit its invitees to use in common with others the Common Areas
(as defined in Section 4.4) of the Building.  Such rights shall always be
subject to reasonable rules and regulations from time to time established by
Landlord by written notice to Tenant in advance and to the right of Landlord to
reasonably designate and change from time to time any Common Areas provided
Tenant is given written notice before any such change.

2.3  TERM.

     The Premises are leased for the Term unless the Term shall sooner terminate
pursuant to any of the terms of this Lease or pursuant to Law.

                                  ARTICLE III
                       DELIVERY OF PREMISES; CONSTRUCTION

3.1  INITIAL CONSTRUCTION.

As indicated in the Work Letter Agreement attached hereto as Exhibit B (the
                                                             ---------
"Work Letter"), Landlord shall complete the Landlord's Work (as defined in the
Work Letter) on the terms, conditions and provisions set forth in the Work
Letter.  Except for Landlord's Work, Landlord is leasing the Premises to Tenant
"as is," without any representations or warranties of any kind (including,
without limitation, any express or implied warranties of merchantability,
fitness or
<PAGE>

habitability), subject to all recorded matters, laws, ordinances, and
governmental regulations and orders.

3.2  DELIVERY OF POSSESION AND COMMENCEMENT DATE.

For purposes of determining the Commencement Date only, the Premises shall be
considered as delivered upon the first to occur of:

     (a) the date on which (i) Landlord or Landlord's architect gives notice of
Substantial Completion (as hereinafter defined) of Landlord's Work; provided
that Substantial Completion has occurred on said date, and (ii) Landlord has
delivered actual possession of the Premises to Tenant free of all tenants and
occupants; or

     (b) if the date of Substantial Completion of Landlord's Work is delayed by
reason of Tenant Delays (as defined in the Work Letter), the date on which, in
Landlord's reasonable judgment, Landlord's Work would have been Substantially
Completed but for such Tenant Delays.

     "Substantial Completion"  of Landlord's Work shall mean (i) completion of
      ----------------------
Landlord's Work except for items which can be completed after Tenant's occupancy
without undue interference with Tenant's use of the Premises ("Punchlist Items")
and (ii) the issuance of a certificate of occupancy for the Premises with
respect to Landlord's Work.  Landlord shall use reasonable efforts to complete
all Punchlist Items within thirty days or, if such completion is not feasible
for any reason, as soon as conditions permit, and Tenant shall afford Landlord
access to the Premises for such purpose pursuant to the terms of this Lease,
provided that Landlord does not unreasonably interfere with Tenant's use or
occupancy of the Premises.

The Commencement Date shall not, however, be earlier than March 15, 2000.

3.3  CONCLUSIVENESS OF LANDLORD'S PERFORMANCE.

Except for latent defects, and except to the extent Tenant shall have given
Landlord notice not later than 90 days after the Commencement Date of defects in
Landlord's Work, Tenant shall have no claim that Landlord has failed to perform
any of Landlord's Work.

3.4  GENERAL PROVISIONS APPLICABLE TO CONSTRUCTION.

     Tenant shall not make any installations, alterations, additions, or
improvements in or to the Premises, including, without limitation, any apertures
in the walls, partitions, ceilings or floors, without on each occasion obtaining
the prior written consent of Landlord, which shall not be unreasonably withheld
or delayed.  Tenant shall reimburse Landlord for all costs incurred by Landlord
or any Superior Mortgagee (as defined below) in reviewing Tenant's proposed
installation, alterations, additions or improvements, and provided further that,
in order to protect the functional integrity of the Premises, all such
installations, alterations, additions or

<PAGE>

improvements shall be performed by contractors selected from a list of approved
contractors prepared by Landlord from time to time. Any such work so approved by
Landlord shall be performed only in accordance with plans and specifications
therefor approved by Landlord. Tenant shall procure at Tenant's sole expense all
necessary permits and licenses before undertaking any work on the Premises and
shall perform all such work in a good and workmanlike manner employing materials
of good quality and so as to conform with all applicable insurance requirements,
laws, ordinances, regulations and orders of governmental authorities. Tenant
shall employ for such work only contractors approved by Landlord, which approval
shall not be unreasonably withheld, and shall require all contractors employed
by Tenant to carry worker's compensation insurance in accordance with statutory
requirements and commercial general liability insurance covering such
contractors on or about the Premises with a combined single limit not less than
$3,000,000 and shall submit certificates evidencing such coverage to Landlord
prior to the commencement of such work. Tenant shall indemnify and hold harmless
Landlord from all injury, loss, claims or damage to any person or property
occasioned by or growing out of such work. Landlord may inspect the work of
Tenant at reasonable times and give notice of observed defects. Upon completion
of any such work, Tenant shall provide Landlord with "as built" plans, copies of
all construction contracts and proof of payment for all labor and materials.

Tenant covenants and agrees that with respect to the carpentry work on any and
all alterations, improvements and/or additions that are made to the Premises,
Tenant's construction managers, general contractors and subcontractors shall be
signatory to and in good standing under the Carpenters Union collective
bargaining agreement covering the geographical area where the work is performed,
and with respect to non-carpentry work, wherever possible, such work shall be
performed by contractors signatory to and in good standing under the collective
bargaining agreement of the local building trades union affiliated with the
AFL-CIO which covers that work.  If the construction manager, general contractor
and/or subcontractor with responsibility for the carpentry work is not signatory
to and in good standing under the Carpenters Union's collective bargaining
agreement, then the Landlord shall have the right, upon 24 hours' written notice
to Tenant, to order Tenant to cease all work on the Premises, in which event all
work then in progress shall be halted and shall not be recommenced until and
unless Tenant's construction manager, general contractor and/or subcontractor
becomes subject to or covered by and in good standing under the Carpenters
Union's collective bargaining agreement.

                                  ARTICLE IV
                                     RENT

4.1  BASE RENT.

     Beginning on the Base Rent Commencement Date, Tenant agrees to pay rent to
Landlord without notice or demand and without any offset or reduction whatever
(except as made in accordance with the express provisions of this Lease), equal
to the Base Rent in equal installments in advance on the first day of each
calendar month included in the Term.  If the Base Rent Commencement Date occurs
on a day other than the first day of a calendar month, Tenant
<PAGE>

shall pay to Landlord, on the Commencement Date, Base Rent for the partial month
after the Commencement Date at the proportionate rate payable for such portion.

4.2  ADDITIONAL RENT.

All sums payable by Tenant under this Lease other than Base Rent shall be deemed
"Additional Rent;" the term "Rent" shall mean Base Rent and Additional Rent.
Landlord shall reasonably estimate in advance by written notice to Tenant at
least thirty days in advance and beginning on the Commencement Date Tenant shall
pay the following costs (the "Total Operating Costs"), to be paid with the Base
Rent throughout the Term in equal monthly installments based on Landlord's most
recent reasonable estimate: (i) all Real Property Taxes for which Tenant is
liable under Section 4.3 of the Lease, (ii) all utility costs (if not separately
metered) for which Tenant is liable under Section 6.1.1 of the Lease, and (iii)
all CAM Expenses for which Tenant is liable under Section 4.4 of the Lease.
Landlord may adjust its estimates of Total Operating Costs at any time based
upon Landlord's experience and reasonable anticipation of costs, upon at least
ten business days prior written notice specifying the reasons for any
adjustments.  Such adjustments shall be effective as of the next Rent payment
date after notice to Tenant.  Within 90 days after the end of each fiscal year
(which shall be January 1 through December 31 for this Lease) during the Term,
Landlord shall deliver to Tenant a statement (the "Statement") prepared in
accordance with generally accepted accounting principles setting forth, in
reasonable detail, the Total Operating Costs paid or incurred by Landlord during
the preceding fiscal year.  Within thirty days after Tenant's receipt of such
Statement, there shall be an adjustment made in good faith between Landlord and
Tenant, with payment to or credit given by Landlord (as the case may be) in
order that Landlord shall have received the actual amount of Total Operating
Costs for such period. Tenant (and its accountants and representatives) shall
have the right, within thirty days of receipt of the Statement, to notify
Landlord that it would like to audit Landlord's books and records with respect
to the Total Operating Costs.  Such audit is to be at Tenant's sole cost and
expense (except as provided in the following sentence) and is to performed and
completed within two months of the receipt of the Statement by Tenant. .  If
such audit reveals that Total Operating Costs billed to Tenant exceed the actual
Total Operating Costs by more than ten percent, Landlord shall pay to Tenant the
reasonable costs of such audit and Landlord will refund to Tenant the amount of
any such overpayment.

     In addition to its obligation to pay Base Rent and Total Operating
Expenses, Tenant is required hereunder to pay directly to suppliers, vendors,
carriers, contractors, etc. certain insurance premiums, utility costs, personal
property taxes, cleaning and other expenses (collectively "Additional
Expenses").  If Landlord pays for any Additional Expenses in accordance with the
terms of this Lease, Tenant's obligation to reimburse such costs shall be an
Additional Rent obligation.  Unless this Lease provides otherwise, Tenant shall
pay all Additional Rent then due with the next monthly installment of Base Rent
due after Tenant received written notice of the amount of such Additional Rent.
<PAGE>

4.3  REAL PROPERTY TAXES.

     Tenant shall pay its Pro Rata Share of all Real Property Taxes on the
Property attributable to any period included in the Term; provided, however, if
the Term includes only a portion of a fiscal tax period, the Real Property Taxes
for such period shall be prorated according to the fraction of the total days in
such period falling within the Term, and Tenant shall be responsible for paying
only such prorated amount. The term "Real Property Taxes" shall mean taxes,
assessments (special, betterment, or otherwise), levies, fees, rent taxes,
impositions, excises, charges, water and sewer rents and charges, and all other
government levies and charges, general and special, ordinary and extraordinary,
foreseen and unforeseen, which are imposed or levied upon or assessed against
the Premises or any Rent or other sums payable by any tenants or occupants
thereof.  If at any time during the term the present system of ad valorem
taxation of real property shall be changed so that in lieu of the whole or any
part of the ad valorem tax on real property, or in lieu of increases therein,
there shall be assessed on Landlord a capital levy or other tax on the gross
rents received with respect to the Property or a federal, state, county,
municipal, or other local income, franchise, excise or similar tax, assessment,
levy, or charge (distinct from any now in effect) measured by or based, in whole
or in part, upon gross rents, then all of such taxes, assessments, levies, or
charges, to the extent so measured or based, shall be deemed to be a Real
Property Tax.  Notwithstanding any other provision of this Lease, Real Property
Taxes shall not include, and Tenant shall have no obligation to pay, any taxes
on Landlord's net income.  Landlord shall have the right, but not the
obligation, to dispute any Real Property Taxes attributable to any fiscal tax
period included wholly or partially within the Term.  The cost of such review
and/or contest shall be included in the calculation of Total Operating Costs.

4.4  CAM EXPENSES.

     "CAM Expenses" are all out-of-pocket costs and expenses paid or incurred by
Landlord in connection  with the operation and maintenance of the Common Areas
(as defined below), the Property and the repair and maintenance of the heating,
ventilation, air conditioning, plumbing, electrical, utility, and safety
systems, including, but not limited to, the following:  gardening and
landscaping; snow removal; utility, water and sewage services for the Common
Areas or provided to all tenants of the Property; maintenance of signs; worker's
compensation insurance; personal property taxes; rental or lease payments for
rented or leased personal property used in the operation or maintenance of the
Common Areas; fees for required licenses and permits; routine maintenance,
repair and replacement of roof membrane, flashings, gutters, downspouts, roof
drains, skylights and waterproofing; repair, maintenance and replacement of
paving (including sweeping, striping, repairing, resurfacing and repaving);
general maintenance; painting; lighting; cleaning; refuse removal; payroll of
maintenance personnel and management personnel not above the level of property
manager; security guards; a property management fee (not to exceed 5% of the net
income of the Property); and premiums for the insurance carried by Landlord
pursuant to Section 5.1.4 of this Lease. Notwithstanding any other provision of
this Lease, CAM Expenses shall not, however, include the following:  leasing
commissions,
<PAGE>

advertising expenses, legal fees and other costs in leasing and procuring new
tenants for the Property; expenditures for capital improvements except (i)
capital expenditures which Landlord reasonably anticipates will have the effect
of reducing current and/or future CAM Expenses and (ii) capital expenditures
required by laws enacted or regulations promulgated after the date of this lease
(provided, however, only an amortized portion of any capital expenditures
permitted to be included in CAM Expenses shall be included in CAM Expenses for
the year in which the expenditures are incurred and subsequent years, on a
straight line basis, over an appropriate useful life, with an interest factor
reasonably determined by Landlord at the time of Landlord's having incurred said
expenditure); cost of repairs or replacements incurred by reason of fire or
other casualty or by the exercise of the right of eminent domain to the extent
to which Landlord is compensated therefor through proceeds of insurance or a
condemnation award; accounting and legal fees and other expenses incurred in
disputes with tenants; costs incurred in performing work or furnishing services
exclusively to or for the benefit of individual tenants or prospective tenants
and which are separately billed to such tenants, including, but not limited to
painting, redecorating and after hours HVAC; payments of principal, interest and
other charges under any Superior Mortgage or rent and other charges payable
under any Superior Lease; salaries, wages, benefits and other expenses of
administrative employees and other employees involved in the operation or
management of the Property above the level of property manager; compensation
paid to employees or other persons in connection with commercial concessions
operated by Landlord; and Landlord's general overhead not directly related to
the operation or maintenance of the Property.

     As used in this Lease, "Common Areas" shall mean all areas within the
Property (and located on property adjacent to the Property of which the Property
has the beneficial use) which are not part of the rentable areas of the
Property, including, but not limited to, lobbies, loading docks, parking areas,
driveways, sidewalks, access roads, landscaping, and planted areas.  Landlord,
from time to time, may change the size, location, nature, and use of any of the
Common Areas, convert Common Areas into leasable areas, construct additional
parking facilities (including parking structures), and increase or decrease
Common Area land or facilities.  Tenant acknowledges that such activities may
result in inconvenience to Tenant.

4.5  PAYMENTS.

     All payments of Rent shall be made to Landlord at Landlord's Notice
Address, or to such other person as Landlord may from time to time designate by
written notice to Tenant. If any installment of Rent is paid more than 5 days
after the due date thereof, at Landlord's election, it shall bear interest from
such due date at a rate equal to the average prime commercial rate from time to
time established by BankBoston plus 4% per annum, which interest shall be
immediately due and payable as further Additional Rent.  Interest shall not,
however, be charged with respect to the first two times, if any, in each Lease
Year, that a Rent payment is more than 5 days late.
<PAGE>

                                   ARTICLE V
                             LANDLORD'S COVENANTS

5.1  LANDLORD'S COVENANTS DURING THE TERM.

     Landlord covenants during the Term:

     5.1.1  Repairs and Maintenance. Except as provided in Article VII, Landlord
            -----------------------
shall perform all maintenance, repairs and replacements necessary to keep in
good condition and working order, and in compliance with all applicable laws,
the foundation, columns, exterior walls, floors, roof and other structural
elements of the Building (collectively, "Structural Components"), and the
outdoor lighting, sprinkler system, Building electrical system, Building pipes
and plumbing system, all Common Areas, the HVAC system and all other mechanical
systems and equipment of the Building. Within a reasonable time after receiving
actual knowledge thereof, Tenant shall notify Landlord of any maintenance within
the Premises that Landlord is obligated to perform pursuant to this Section
5.1.1.


     5.1.2  Quiet Enjoyment. That Landlord has the right to make this Lease and
            ---------------
that Tenant on paying the Rent and performing its obligations hereunder shall
peacefully and quietly have, hold and enjoy the Premises throughout the Term
without any manner of hindrance or molestation from Landlord or anyone claiming
under Landlord, subject however to all the terms and provisions hereof.

     5.1.3  Insurance. During the Term, Landlord shall maintain in effect all
            ---------
risk insurance covering loss of or damage to the Building and other improvements
at the Property in the amount of its replacement value with such endorsements
and deductibles as Landlord shall reasonably determine from time to time.
Landlord shall have the right to obtain flood, earthquake, and such other
insurance as Landlord shall reasonably determine from time to time or shall be
required by any lender holding a security interest in the Premises. Landlord
shall not obtain insurance for Tenant's trade fixtures, equipment or building
improvements. During the Term, Landlord shall also maintain a rental income
insurance policy, with loss payable to Landlord, in an amount equal to one
year's Base Rent, plus estimated Real Property Taxes, Operating Costs, and
insurance premiums. Tenant shall not do or permit anything to be done which
shall invalidate any such insurance. Any policy obtained by Landlord shall not
be contributory, shall not provide primary insurance, and shall be excess over
any insurance maintained by Tenant. Landlord shall also maintain during the Term
a policy of general liability insurance with respect to the Premises naming
Tenant as an additional insured, with a cross-liability endorsement.

     5.1.4  Tenant's Access. Tenant shall have access to the Premises at all
            ---------------
times (24 hours each day and seven days each week).
<PAGE>

5.2  INTERRUPTIONS.

     Landlord shall not be liable to Tenant for any compensation or reduction of
Rent by reason of inconvenience or annoyance or for loss of business arising
from power losses or shortages or from the necessity of Landlord's entering the
Premises for any of the purposes in this Lease authorized, or for repairing the
Premises or any portion thereof unless such event is caused by Landlord's
negligence. In case Landlord is prevented or delayed from making any repairs,
alterations or improvements, or furnishing any service or performing any other
covenant or duty to be performed on Landlord's part, by reason of any cause
beyond Landlord's reasonable control, Landlord shall not be liable to Tenant
therefor, nor, except as expressly otherwise provided in Article VII, shall
Tenant be entitled to any abatement or reduction of rent by reason thereof, nor
shall the same give rise to a claim in Tenant's favor that such failure
constitutes actual or constructive, total or partial, eviction from the
Premises.

     Landlord reserves the right to stop any service or utility system when
necessary by reason of accident or emergency acting in good faith, until
necessary repairs have been completed. Except in case of emergency repairs,
Landlord will give Tenant reasonable advance written notice of any contemplated
stoppage and will use reasonable efforts to avoid unnecessary inconvenience to
Tenant by reason thereof.

     Landlord also reserves the right, by written notice to Tenant at least 10
days in advance, to institute such policies, programs and measures as may be
required to comply with applicable codes, rules, regulations or standards.

                                  ARTICLE VI
                              TENANT'S COVENENTS

6.1  TENANT'S COVENANTS DURING THE TERM.

     Tenant covenants during the Term and such further time as Tenant occupies
any part of the Premises:

     6.1.1  Tenant's Payments. To pay when due (a) all Base Rent and Additional
            -----------------
Rent, (b) all taxes which may be imposed on Tenant's personal property in the
Premises (including, without limitation, Tenant's fixtures and equipment)
regardless to whomever assessed, (c) all charges by public utilities for
telephone, electricity and other utility services (including service inspections
therefor) rendered to the Premises, and (d) as Additional Rent, all other
charges payable to Landlord pursuant to this Lease.

     6.1.2  Repairs and Yielding Up. Except as otherwise provided in Article
            -----------------------
VII, at Tenant's sole expense to keep the Premises in as good order, repair and
condition as exists on the Commencement Date or in such improved condition as it
may be put during the Lease Term, reasonable wear and damage by fire, casualty
and eminent domain excepted, and to make all
<PAGE>

necessary and customary repairs thereto in order to do so; and at the expiration
or termination of this Lease peaceably to yield up the Premises and all changes
and additions therein in good order, repair and condition, first removing all
goods and effects of Tenant and any items, the removal of which is required by
agreement or specified herein to be removed at Tenant's election and which
Tenant elects to remove, and repairing all damage caused by such removal and
restoring the Premises and leaving them clean and neat.

     6.1.3  Cleaning. At its sole cost and expense enter into a service contract
            --------
to provide for the cleaning of the Premises. Such cleaning contracts and the
vendors thereunder shall be subject to Landlord's reasonable approval.

     6.l.4  Occupancy and Use. Continuously from the Commencement Date, to use
            -----------------
and occupy the Premises only for the Permitted Uses; not to injure or deface the
Premises; and not to permit in the Premises any use thereof which is contrary to
law or ordinances, or creates a nuisance or to render necessary any alteration
or addition to the Building; not to dump, flush, or in any way introduce any
hazardous substances or any other toxic substances into the septic, sewage or
other waste disposal system serving the Premises, not to generate, store or
dispose of hazardous substances in or on the Premises or dispose of hazardous
substances from the Premises to any other location without the prior written
consent of Landlord, which shall not be unreasonably withheld, delayed or
conditioned, and then only in compliance with all applicable laws, ordinances
and regulations; to notify Landlord of any incident which would require the
filing of a notice under applicable federal, state, or local law; not to store
or dispose of hazardous substances on the Premises without first submitting to
Landlord a list of all such hazardous substances and all permits required
therefor and thereafter providing to Landlord on an annual basis Tenant's
certification that all such permits have been renewed with copies of such
renewed permits; and to comply with the orders and regulations of all
governmental authorities with respect to zoning, building, fire, health and
other codes, regulations, ordinances or laws, to the extent applicable to
Tenant's use of the Premises. "Hazardous substances" as used in this paragraph
shall mean "hazardous substances" as defined in the Comprehensive Environmental
Response Compensation and Liability Act of 1980, as amended, 42 U.S.C. (S)9601
and regulations adopted pursuant to said Act, provided, however, "hazardous
substances" shall not include customary quantities of ordinary office and
cleaning products, fuel for any generators on the Premises.

     6.1.5  Rules and Regulations/Security. To comply with any reasonable rules
            ------------------------------
and regulations hereafter made by Landlord, of which Tenant has been given
notice, for the care and use of the Premises and the Property. To provide, at
its sole cost and expense, any security system serving the Premises. Tenant
acknowledges that Landlord is not providing any security system or security
guards at the Property.

     6.1.6  Safety Appliances. To keep the Premises equipped with all safety
            -----------------
appliances required by law or ordinance or any other regulation of any public
authority because of any use made by Tenant and to procure all licenses and
permits so required because of such use and, if reasonably requested by
Landlord, to do any work so required because of such use, it being
<PAGE>

understood that the foregoing provisions shall not be construed to broaden in
any way Tenant's Permitted Uses.

     6.1.7  Assignment and Subletting. Not without the prior written consent of
            -------------------------
Landlord, which consent shall not be unreasonably withheld or delayed, to assign
this Lease, to make any sublease, or to permit occupancy of the Premises or any
part thereof by anyone other than Tenant, voluntarily or by operation of law; as
Additional Rent, to reimburse Landlord promptly for reasonable and customary
legal and other expenses (up to $1,500 per occurrence) incurred by Landlord or
any Superior Mortgagee in connection with any request by Tenant for consent to
assignment or subletting; no assignment or subletting shall affect the
continuing primary liability of Tenant (which, following assignment, shall be
joint and several with the assignee); no consent to any of the foregoing in a
specific instance shall operate as a waiver in any subsequent instance.
Landlord's consent to any proposed assignment or subletting is required both as
to the terms and conditions thereof, and as to the creditworthiness of the
proposed assignee or subtenant and the consistency of the proposed assignee's or
subtenant's business with the Permitted Uses of the Premises. In the event that
any assignee or subtenant pays to Tenant any consideration attributable to the
interest in this Lease or the Premises so assigned or subleased in excess of the
Rent then payable hereunder, or pro rata portion thereof on a square footage
basis for any portion of the Premises, after deducting Tenant's reasonable
attorneys' fees, brokerage commissions and other expenses relating to such
assignment or sublease, Tenant shall promptly pay 50% of said net excess to
Landlord as and when received by Tenant. If a Tenant requests Landlord's consent
to assign this Lease or sublet more than 1/3 of the Premises, or the assignment
or sublease term will begin three or fewer months before the end of the Lease
Term, Landlord shall have the option, exercisable by written notice to Tenant
given within 10 days after receipt of such request, to terminate this Lease as
of a date specified in such notice which shall be not less than 30 days after
the date of such notice.

Notwithstanding the foregoing, Tenant shall have the right, without Landlord's
consent, to assign this Lease to an affiliate of Tenant; provided, however,
Tenant shall provide Landlord fifteen (15) business days' prior written notice
to Landlord and shall provide evidence reasonably acceptable to Landlord that
the assignee shall have a net worth and creditworthiness at least equal to the
greater of (i) Tenant's net worth and creditworthiness on the date of this Lease
or (ii) Tenant's net worth and creditworthiness on the date of such notice.

     6.l.8  Indemnity. To defend, with counsel approved by Landlord, all actions
            ---------
against Landlord, its officers, directors, members, employees, agents, advisors
and contractors and all others who could be liable for the obligations of any of
them, and any holders of mortgages secured by the Property ("Indemnified
Parties") with respect to, and to indemnify and save harmless, to the extent
permitted by law, all Indemnified Parties from and against, any and all
liabilities, losses damages, costs, expenses (including reasonable attorneys'
fees and expenses), causes of action, suits, claims, demands or judgments of any
nature (a) to which any Indemnified Party is subject because of its estate or
interest in the Property, or (b) arising from (i) injury to or death of any
person, or damage to or loss of property, on the Property, or connected with the
use, condition or occupancy of any thereof, (ii) a breach of Tenant's
obligations under this Lease, or (iii) any act, negligence or willful misconduct
of Tenant or its employees, agents, contractors,
<PAGE>

licensees, sublessees or invitees; except to the extent arising from the gross
negligence or willful misconduct of Landlord or any Indemnified Party.

     6.1.9  Tenant's Liability Insurance.
            ----------------------------

            a.   Liability Insurance. To maintain in effect commercial general
                 -------------------
liability insurance insuring Tenant against liability for bodily injury,
property damage (including loss of use of property) and personal injury at the
Premises. Such insurance shall name Landlord, its property manager, any
mortgagee of which Tenant has received written notice, and Great Point Investors
LLC, as additional insureds. The initial amount of such insurance shall be One
Million Dollars ($1,000,000) per occurrence, Two Million Dollars ($2,000,000) in
the aggregate, and shall be subject to reasonable periodic increases specified
by Landlord based upon inflation, increased liability awards, recommendation of
Landlord's professional insurance advisers, and other relevant factors. The
liability insurance obtained by Tenant under this Section 6.1.8 shall (i) be
primary and (ii) insure Tenant's obligation to Landlord under Section 6.1.7
under a standard contractual liability endorsement. The amount and coverage of
such insurance shall not limit Tenant's liability nor relieve Tenant of any
other obligation under this Lease.

            b.   Worker's Compensation Insurance. To maintain in effect Worker's
                 -------------------------------
Compensation Insurance (including Employees' Liability Insurance) in the
statutory amount covering all employees of Tenant employed or performing
services at the Premises, in order to provide the statutory benefits required by
the laws of the state in which the Premises are located.

            c.   Automobile Liability Insurance. To maintain in effect
                 ------------------------------
Automobile Liability Insurance, including but not limited to, passenger
liability, on all owned, nonowned, and hired vehicles used in connection with
the Premises, with a combined single limit per occurrence of not less than One
Million Dollars ($1,000,000) per vehicle for injuries or death of one or more
persons or loss or damage to property.

            d.   Personal Property Insurance. To maintain in effect Personal
                 ---------------------------
Property Insurance covering Tenant's personal property and trade fixtures from
time to time in, on, or at the Premises, in an amount not less than 100% of the
full replacement cost, without deduction for depreciation, providing protection
against events protected under "All Risk Coverage," as well as against sprinkler
damage, vandalism, and malicious mischief. Any proceeds from the Personal
Property Insurance shall be used for the repair or replacement of the property
damaged or destroyed, unless this Lease is terminated under an applicable
provision herein.

            e.   Business Interruption Insurance. To maintain in effect Business
                 -------------------------------
Interruption Insurance, providing in the event of damage or destruction of the
Premises an amount sufficient to sustain Tenant for a period of not less than
one year for: (i) the net profit that would have been realized had Tenant's
business continued; and (ii) such fixed charges and expenses as must necessarily
continue during a total or partial suspension of business to the extent to which
they would have been incurred had no business interruption occurred, including,
but not limited to, interest on indebtedness of Tenant, salaries of executives,
foremen, and other employees under contract, charges under noncancelable
contracts, charges for advertising, legal
<PAGE>

or other professional services, taxes and rents that may still continue, trade
association dues, insurance premiums, and depreciation.

             f.  General Insurance Provisions.
                 ----------------------------

                 (i)   Any insurance which Tenant shall be required to maintain
under this Lease shall include a provision which requires the insurance carrier
to give Landlord not less than 30 days' written notice prior to any cancellation
or modification of such coverage.

                 (ii)  Prior to the earlier of Tenant's entry into the Premises
or the Commencement Date, Tenant shall deliver to Landlord an insurance company
certificate that Tenant maintains the insurance required by Sections 6.1.8(a)-
(e) and not less than 30 days prior to the expiration or termination of any such
insurance, Tenant shall deliver to Landlord renewal certificates therefor.
Tenant shall provide Landlord with copies of the policies promptly upon request
from time to time. If Tenant shall fail to deliver any certificate or renewal
certificate to Landlord required under this Lease within the prescribed time
period or if any such policy shall be canceled or modified in a manner
materially adverse to Landlord during the Lease Term without Landlord's consent,
Landlord may, after notice and the expiration of the applicable grace period,
obtain such insurance, in which case Tenant shall reimburse Landlord, as
Additional Rent, for the cost of procuring such insurance within 10 days after
receipt of a statement of the cost of such insurance. Each time, if any, Tenant
exercises a renewal right pursuant to Article 10 of this Lease, Landlord shall
have the right to reasonably adjust or modify the terms of Tenant's insurance
requirements hereunder.

                 (iii) Tenant shall maintain all insurance required under this
Lease with companies having a "General Policy Rating" of A-X or better, as set
forth in the most current issue of the Best Key Rating Guide. Landlord and
Tenant, on behalf of themselves and their insurers, each hereby waive any and
all rights of recovery against the other, or against the officers, partners,
members, employees, agents, or representatives of the other, for loss of or
damage to its property or the property of others under its control, if such loss
or damage shall be covered by any insurance policy in force (whether or not
described in this Lease) at the time of such loss or damage. All property
insurance carried by either party shall contain a waiver of subrogation against
the other party to the extent such right shall have been waived by the insured
party prior to the occurrence of loss or injury.

     6.1.10  Landlord's Right of Entry. To permit Landlord and Landlord's agents
             -------------------------
entry upon reasonable advance notice and without material interference with
Tenant's use of the Premises: to examine the Premises at reasonable times and,
if Landlord shall so elect, to make repairs or replacements as required or
permitted by this Lease; to remove, at Tenant's expense, any changes, additions,
signs, curtains, blinds, shades, awnings, aerials, flagpoles, or the like not
consented to in writing (to the extent required under this Lease); and to show
the Premises to prospective tenants during the 12 months preceding expiration of
the Term and to prospective purchasers and mortgagees at all reasonable times.
<PAGE>

     6.1.11  Loading. Not to place Tenant's property (as described in Section
             -------
6.1.12), upon the Premises so as to exceed the floor load capacities; Tenant's
business machines and mechanical equipment which cause vibration or noise that
may be transmitted to the Building structure shall be placed and maintained by
Tenant in settings of cork, rubber, spring, or other types of vibration
eliminators sufficient to eliminate such vibration or noise,

     6.1.12  Landlord's Costs. In case Landlord shall be made party to any
             ----------------
litigation commenced by or against Tenant or by or against any parties in
possession of the Premises or any part thereof claiming under Tenant, except any
litigation arising out of a breach by Landlord of its obligations under this
Lease or the negligence or willful misconduct of Landlord or its agents,
employees or contractors (unless Landlord is the prevailing party in such
litigation), to pay, as Additional Rent, all reasonable costs including, without
implied imitation, reasonable counsel fees incurred by or imposed upon Landlord
in connection with such litigation and, as Additional Rent, also to pay all such
costs and fees incurred by Landlord in connection with the successful
enforcement by Landlord of any obligations of Tenant under this Lease.

     6.l.l3  Tenant's Property. All the furnishings, fixtures, equipment,
             -----------------
effects and property of every kind, nature and description of Tenant and of all
persons claiming by, through or under Tenant which, during the continuance of
this Lease or any occupancy of the Premises by Tenant or anyone claiming under
Tenant, may be on the Premises, shall be at the sole risk and hazard of Tenant,
and if the whole or any part thereof shall be destroyed or damaged by fire,
water or otherwise, or by the leakage or bursting of water pipes, steam pipes,
or other pipes, by theft, or from any other cause, no part of said loss or
damage is to be charged to or to be borne by Landlord, unless due to the gross
negligence of Landlord.

     6.1.14  Labor or Materialmen's Liens. To pay promptly when due the entire
             ----------------------------
cost of any work done on the Premises by Tenant, its agents, employees, or
independent contractors; not to cause or permit any liens for labor or materials
performed or furnished in connection therewith to attach to the Premises; and to
discharge any such liens which may so attach within five business days after
receiving notice of such liens. Notwithstanding the foregoing, if Tenant is in
a dispute with another party with respect to work performed at the Premises,
Tenant may withhold payment provided that Tenant posts a bond reasonably
acceptable to Landlord pending the resolution of such dispute.

     6.l.l5  Holdover. (A) (i) For the first two months or portion thereof that
             --------
Tenant shall retain possession of the Premises, to pay Landlord 150% of the
total of the Base Rent and Additional Rent then applicable for each month or
portion thereof and (ii) thereafter, to pay Landlord 200% of the greater of the
total of the Base Rent and Additional Rent then applicable for each month or
portion thereof; and (B) also to pay all damages sustained by Landlord on
account thereof.  The provisions of this Subsection 6.1.15 shall not operate as
a waiver by Landlord of the right of re-entry provided in this Lease.
<PAGE>

                                  ARTICLE VII
                              CASUALTY AND TAKING

7.1  CASUALTY AND TAKING.

     In case during the Term all or any substantial part of the Premises, are
damaged materially by fire or any other cause, or by action of public or other
authority in consequence thereof, or are taken by eminent domain, either
Landlord or Tenant shall have the right to terminate this Lease, by notice to
Tenant within 30 days after the occurrence of the event giving rise to the
election to terminate, which notice shall specify the effective date of
termination which shall be not less than 30 nor more than 60 days after the date
of notice of such termination. If Landlord does not terminate this Lease as
provided above, Landlord shall use due diligence to restore the Premises, or, in
case of a taking, what may remain thereof (excluding any items installed or paid
for by Tenant which Tenant may be required or permitted to remove) into proper
condition for use and occupation to the extent permitted by the net award of
insurance or damages available to Landlord, and a just proportion of the Base
Rent according to the nature and extent of the injury shall be abated until the
Premises or such remainder shall have been restored by Landlord to such
condition; and in case of a taking which permanently reduces the area of the
Premises, a just proportion of the Base Rent and shall be abated for the
remainder of the Term.

7.2  RESERVATION OF AWARD.

     Landlord reserves to itself any and all rights to receive awards made for
damages to the Premises and the leasehold hereby created, accruing by reason of
exercise of eminent domain or by reason of anything lawfully done in pursuance
of public or other authority. Tenant hereby releases and assigns to Landlord all
Tenant's rights to such awards, and covenants to deliver such further
assignments and assurances thereof as Landlord may from time to time request.
and hereby irrevocably designates and appoints Landlord its attorney- in-fact to
execute and deliver in Tenant's name and behalf all such further assignments
thereof. It is agreed and understood, however, that Landlord does not reserve to
itself, and Tenant does not assign to Landlord, any damages payable for (i)
trade fixtures installed by Tenant or anybody claiming under Tenant, at its own
expense or (ii) relocation expenses recoverable by Tenant from such authority in
a separate action.

                                 ARTICLE VIII
                              RIGHTS OF MORTGAGEE

8.1  SUBORDINATION.

     This Lease and all rights of Tenant hereunder shall be subject and
subordinate in all respects to (a) all present and future ground leases,
operating leases, superior leases, overriding
<PAGE>

leases and underlying leases and grants of term of the Premises or any portion
thereof (collectively, including the applicable items set forth in Subdivision
(d) of this Section 8.1, the "Superior Lease") whether or not the Superior Lease
shall also cover other lands or buildings, (b) all mortgages and building loan
agreements, including leasehold mortgages, which may now or hereafter affect the
Premises or the Superior Lease (collectively, including the applicable items set
forth in Subdivisions (c) and (d) of this Section 8.1, the "Superior Mortgage"),
whether or not any Superior Mortgage shall also cover other lands or buildings
or leases, (c) each advance made or to be made under any Superior Mortgage, and
(d) all renewals, modifications, replacements, substitutions and extensions of
the Superior Lease and any Superior Mortgage. Any holder of a Superior Mortgagee
(a "Superior Mortgagee") may elect that this Lease shall have priority over such
Superior Mortgage and, upon notification thereof by such Superior Mortgagee to
Tenant, this Lease shall be deemed to have priority over such Superior Mortgage,
whether this Lease is dated prior to or subsequent to the date of such Superior
Mortgage. If, in connection with the obtaining, continuing or renewing of
financing for which the Premises or the interest of the lessee under the
Superior Lease represents collateral, in whole or in part, any bank, insurance
company, pension fund or other lending institution shall request reasonable
modifications of this Lease as a condition of its granting such financing,
Tenant will not unreasonably withhold its consent thereto, provided that such
modifications do not increase the Base Rent, materially and adversely increase
the obligations of Tenant hereunder or materially and adversely affect Tenant's
rights hereunder. Tenant agrees that it will take no steps to terminate this
Lease or abate Rent payable hereunder without giving each lessor under a
Superior Lease (a "Superior Lessor"), and any Superior Mortgagee requesting
same, written notice of any default by Landlord and the opportunity to cure such
default (without any obligation on the part of any such person to cure such
default) within 45 days thereafter or, if such Superior Lessor or Superior
Mortgagee commences such cure within 30 business days and diligently pursues
such cure, such longer period as may be reasonably necessary to effect such
cure. Landlord shall endeavor to obtain a subordination and non-disturbance
agreement, in recordable form, for each present and future Superior Mortgagee or
Superior Lessor.

8.2  SUCCESSOR LANDLORD.

     For purposes of this Section 8.2, the term "Successor Landlord" shall mean
and include (i) any person, including but not limited to any Superior Lessor or
Superior Mortgagee, who, prior to the termination of this Lease, acquires or
succeeds to the interest of Landlord under this Lease through summary
proceedings, foreclosure action, assignment, deed in lieu of foreclosure or
otherwise, and (ii) the successors and assigns of any person referred to in
clause (i) of this sentence. Upon any Successor Landlord's so acquiring, or so
succeeding to, the interest of Landlord under this Lease, Tenant shall, at the
election and upon the request of the Successor Landlord, fully attorn to and
recognize such Successor Landlord as Tenant's landlord under this Lease upon the
then executory terms of this Lease, but only if such Successor Landlord is bound
by a Non-Disturbance Agreement and only in accordance with such Non-Disturbance
Agreement. No Successor Landlord shall be bound by any prepayment of rent or
additional rent for more than one month in advance or any amendment or
modification of this Lease made without the consent of the Superior Mortgagee or
Superior Lessor from which such Successor Landlord derives its interest in this
Lease or the Premises. Upon demand of any such Successor
<PAGE>

Landlord, Tenant agrees to execute instruments to evidence and confirm the
foregoing provisions of this Section reasonably satisfactory to any such
Successor Landlord.


8.3  NO PREPAYMENT OR MODIFICATION, ETC.

     Tenant shall not pay Rent, or any other charge more than thirty days prior
to the due date thereof; no prepayment of the Rent (except one monthly
installment of Base Rent) or other charge, no assignment of this Lease and no
agreement to modify the Lease so as to reduce the Rent, change the Term, or
otherwise materially change the rights of Landlord under this Lease, or to
relieve Tenant of any obligations or liability under this Lease, shall be
enforceable against any Superior Mortgagees unless consented to in writing by
all Superior Mortgagees, if any.

                                   ARTICLE IX
                                    DEFAULT

9.1  EVENTS OF DEFAULT.

     There shall be an "Event of Default" hereunder if:

          (i)   any default by Tenant continues after notice (describing such
     default in reasonable detail), (a) in case of the payment of Rent or any
     other monetary obligation to Landlord for more than 5 days (other than the
     first two times in a Lease Year that such a payment is more than 5 days
     late), (b) in case of the delivery of any document to Landlord for more
     than 10 days or (c) in any other case for more than 30 days and such
     additional time, if any, as is reasonably necessary to cure the default if
     the default is of such a nature that it cannot reasonably be cured in 30
     days and Tenant diligently commences and continues to cure such default and
     completes such cure within 90 days; or

          (ii)  if Tenant becomes insolvent, fails to pay its debts as they fall
     due, files a petition under any chapter of the U.S. Bankruptcy Code, 11
     U.S.C, 101 et seq., as it may be amended (or any similar petition under any
     insolvency law of any jurisdiction), or if such petition is filed against
     Tenant and not dismissed within 60 days; or

          (iii) if Tenant proposes any dissolution, liquidation, composition,
     financial reorganization or recapitalization with creditors, makes an
     assignment or trust mortgage for benefit of creditors, or if a receiver,
     trustee, custodian or similar agent is appointed or takes possession with
     respect to any property of Tenant and such appointment or taking is not
     dismissed within 60 days; or if the leasehold hereby created is taken on
     execution or other process of law in any action against Tenant.
<PAGE>

     If there shall be an Event of Default hereunder, Landlord and the agents
and servants of Landlord may, in addition to and not in derogation of any
remedies for any preceding breach of covenant, immediately or at any time
thereafter while such Event of Default continues and without further notice, at
Landlord's election, do any one or more of the following:

          (a)  give Tenant written notice stating that the Lease is terminated,
effective upon the giving of such notice or upon a date stated in such notice,
as Landlord may elect, in which event the Lease shall be irrevocably
extinguished and terminated as stated in such notice without any further action;
or

          (b)  with process of law, in a lawful manner enter and repossess the
Premises and expel Tenant and those claiming through or under Tenant, and remove
its and their effects, without being guilty of trespass, in which event the
Lease shall be irrevocably extinguished and terminated at the time of such
entry; or

          (c)  pursue any other rights or remedies permitted by law.

     Any such termination of the Lease shall be without prejudice to any
remedies which might otherwise be used for arrears of Rent or prior breach of
covenant, and in the event of such termination Tenant shall remain liable under
this Lease as hereinafter provided. Tenant hereby waives all statutory rights
(including, without limitation, rights of redemption, if any) to the extent such
rights may be lawfully waived, and Landlord, without notice to Tenant, may store
Tenant's effects and those of any person claiming through or under Tenant at the
reasonable expense and risk of Tenant and, if Landlord so elects, may sell such
effects at public auction or private sale and apply the net proceeds to the
payment of all sums due to Landlord from Tenant, if any, and pay over the
balance, if any, to Tenant.

9.2  TENANT'S OBLIGATIONS AFTER TERMINATION.

     In the event that this Lease is terminated under any of the provisions
contained in Section 9.1 or shall be otherwise terminated for breach of any
obligation of Tenant, Tenant covenants to pay forthwith to Landlord, as
compensation, the excess of the total rent reserved for the residue of the Term
over the rental value of the Premises for said residue of the Term. In
calculating the rent reserved and the rental value, there shall be included, in
addition to the Base Rent and all Additional Rent, the value of all other
consideration agreed to be paid or performed by Tenant for said residue. Tenant
further covenants as an additional and cumulative obligation after any such
termination to pay punctually to Landlord all the sums and perform all the
obligations which Tenant covenants in this Lease to pay and to perform in the
same manner and to the same extent and at the same time as if this Lease had not
been terminated. In calculating the amounts to be paid by Tenant under the next
foregoing covenant, Tenant shall be credited with any amount paid to Landlord as
compensation as provided in the first sentence of this Section 9.2 and also with
the net proceeds of any rents obtained by Landlord by reletting the Premises,
after deducting all Landlord's reasonable expenses in connection with such
reletting, including,
<PAGE>

without implied limitation, all repossession costs, brokerage commissions, fees
for legal services and expenses of preparing the Premises for such reletting, it
being agreed by Tenant that Landlord may (i) relet the Premises or any part or
parts thereof for a term or terms which may at Landlord's option be equal to or
less than or exceed the period which would otherwise have constituted the
balance of the Term and may grant such concessions and free rent as Landlord in
its reasonable judgment considers advisable or necessary to relet the same and
(ii) make such alterations, repairs and decorations in the Premises as Landlord
in its sole judgment considers advisable or necessary to relet the same, and no
action of Landlord in accordance with the foregoing or failure to relet or to
collect rent under reletting shall operate or be construed to release or reduce
Tenant's liability as aforesaid.

     Nothing contained in this Lease shall, however, limit or prejudice the
right of Landlord to prove and obtain in proceedings for bankruptcy or
insolvency by reason of the termination of this Lease, an amount equal to the
maximum allowed by any statute or rule of law in effect at the time when, and
governing the proceedings in which, the damages are to be proved, whether or not
the amount be greater, equal to, or less than the amount of the loss or damages
referred to above.


                                   ARTICLE X
                 RIGHT OF RENEWAL; RIGHT OF FIRST NEGOTIATION

10.1  RENEWAL OPTIONS.

      10.1.1   Provided Tenant is not in default under this Lease and that no
event or condition exists which with notice and the expiration of any grace
period would constitute an Event of Default under this Lease at the time the
option may be exercised and at the time the Renewal Period commences, Landlord
grants Tenant options (the "Renewal Options") to extend this Lease with respect
to all of the Premises for two additional consecutive periods of five years
(each a "Renewal Period"). The first Renewal Option shall be exercised by Tenant
delivering written notice to Landlord at least 9 months prior to the Expiration
Date of the initial Term; provided that Tenant has exercised the first Renewal
Option, the second Renewal Option may be exercised by Tenant delivering written
notice to Landlord at least 9 months prior to the Expiration Date of the Term of
the first Renewal Period.

      10.1.2   The rate of annual Base Rent (the "Renewal Rental Rate") for the
first year of each Renewal Period shall be one hundred and three percent (103%)
of the Base Rent in effect for the last Lease Year of the initial Term or
preceding Renewal Period, as applicable, and shall increase by three percent
(3%) for each year thereafter.

      10.1.3   Landlord and Tenant shall execute an amendment to this Lease
within 30 days after the determination of the Renewal Rental Rate, which
amendment shall set forth the extended Term and the Renewal Rental Rate. Except
for the change in the rate of Base Rent, the Renewal Period shall be subject to
all of the terms and conditions of this Lease.
<PAGE>

      10.1.4   Neither any option granted to Tenant in this Lease or in any
collateral instrument to renew or extend the Term, nor the exercise of any such
option by Tenant, shall prevent Landlord from exercising any option or right
granted or reserved to Landlord in this Lease or in any collateral instrument or
that Landlord may otherwise have, to terminate this Lease or any renewal or
extension of the Term either during the original Term or during the renewed or
extended term. Any renewal or extension right granted to Tenant shall be
personal to Tenant and may not be exercised by any assignee, subtenant or legal
representative of Tenant. Any termination of this Lease shall serve to terminate
any such renewal or extension of the Term, whether or not Tenant shall have
exercised any option to renew or extend the Term. No option granted to Tenant to
renew or extend the Term shall be deemed to give Tenant any further option to
renew or extend.

10.2  RIGHT OF FIRST NEGOTIATION.

Provided Tenant is not in default under this Lease beyond any applicable grace
or cure period and that no event or condition exists which with notice and the
expiration of any grace period would constitute an Event of Default under this
Lease at the time the option may be exercised, Landlord shall provide Tenant
with a written notice (an "Availability Notice") of any space at the Property
that is vacated by the prior tenant and is available to re-lease during the Term
of this Lease. Tenant shall have a period (the "Negotiation Period") of 10
business days after receipt of the Availability Notice to negotiate with
Landlord to lease such space. If Landlord and Tenant do not come to agreement
during the Negotiation Period then Landlord shall be free to lease such space.


                                  ARTICLE XI
                                 MISCELLANEOUS

11.1  NOTICES FROM ONE PARTY TO THE OTHER.

      All notices, requests and other communications required or permitted under
this Lease shall be in writing and shall be personally delivered or sent by
certified mail, return receipt requested, postage prepaid or by a national
overnight delivery service which maintains delivery records. Notices to Tenant
and Landlord shall be delivered to the address specified in Article I above. All
notices shall be effective upon delivery (or refusal to accept delivery). Either
party may change its notice address upon notice to the other party.
<PAGE>

11.2  BIND AND INURE.

      The obligations of this Lease shall run with the land, and this Lease
shall be binding upon and inure to the benefit of the parties hereto and their
respective successors and assigns, except that the Landlord named herein and
each successive owner of the Property shall be liable only for the obligations
accruing during the period of its ownership. The obligations of Landlord shall
be binding upon the assets of Landlord which comprise the Property and the
proceeds of any insurance or action in the nature of eminent domain relating to
the Property, but not upon other assets of Landlord. No individual partner,
trustee, stockholder, officer, director, employee, member, beneficiary, agent or
advisor of Landlord shall be personally liable under this Lease and Tenant shall
look solely to Landlord's interest in the Property, and the proceeds of any
insurance or action in the nature of eminent domain relating to the Property
remedies upon an event of default hereunder, and the general assets of the
individual partners, trustees, stockholders, officers, employees, members or
beneficiaries of Landlord shall not be subject to levy, execution or other
enforcement procedure for the satisfaction of the remedies of Tenant.

11.3  NO SURRENDER.

      The delivery of keys to any employee of Landlord or to Landlord's agent or
any employee thereof shall not operate as a termination of this Lease or a
surrender of the Premises.

11.4  NO WAIVER, ETC.

      The failure of Landlord or of Tenant to seek redress for violation of, or
to insist upon the strict performance of any covenant or condition of this Lease
shall not be deemed a waiver of such violation nor prevent a subsequent act,
which would have originally constituted a violation, from having all the force
and effect of an original violation. The receipt by Landlord of Base Rent or
Additional Rent with knowledge of the breach of any covenant of this Lease shall
not be deemed a waiver of such breach by Landlord, unless such waiver is in
writing and signed by Landlord. No consent or waiver, express or implied, by
Landlord or Tenant to or of any breach of any agreement or duty shall be
construed as a waiver or consent to or of any other breach of the same or any
other agreement or duty.

11.5  NO ACCORD AND SATISFACTION.

      No acceptance by Landlord of a lesser sum than the Rent then due shall be
deemed to be other than on account of the earliest installment of such Rent due,
nor shall any endorsement or statement on any check or any letter accompanying
any check or payment as Rent be deemed as accord and satisfaction, and Landlord
may accept such check or payment without prejudice to
<PAGE>

Landlord's right to recover the balance of such installment or pursue any other
remedy in this Lease provided.

11.6  CUMULATIVE REMEDIES.

      The specific remedies to which Landlord may resort under the terms of this
Lease are cumulative and are not intended to be exclusive of any other remedies
or means of redress to which it may be lawfully entitled in case of any breach
or threatened breach by Tenant of any provisions of this Lease. In addition to
the other remedies provided in this Lease, Landlord shall be entitled to the
restraint by injunction of the violation or attempted or threatened violation of
any of the covenants, conditions or provisions of this Lease or to a decree
compelling specific performance of any such covenants, conditions or provisions.

11.7  LANDLORD'S RIGHT TO CURE.

      If Tenant shall at any time default in the performance of any obligation
under this Lease, Landlord shall have the right, but shall not be obligated, to
enter upon the Premises and to perform such obligation, notwithstanding the fact
that no specific provision for such substituted performance by Landlord is made
in this Lease with respect to such default. Except in the case of an emergency
(for which no notice is required), Landlord shall give Tenant two business days'
prior written notice that it will be entering the Premises to perform such
obligation. In performing such obligation, Landlord may make any payment of
money or perform any other act. All sums so paid by Landlord (together with
interest at the rate of 4% per annum in excess of the then average prime
commercial rate of interest being charged by BankBoston) and all necessary
incidental costs and expenses in connection with the performance of any such act
by Landlord, shall be deemed to be Additional Rent under this Lease and shall be
payable to Landlord immediately on demand. Landlord may exercise the foregoing
rights without waiving any other of its rights or releasing Tenant from any of
its obligations under this Lease.

11.8  ESTOPPEL CERTIFICATE.

      Tenant agrees, from time to time, upon not less than 10 days' prior
written request by Landlord, to execute, acknowledge and deliver to Landlord a
statement in writing certifying that this Lease is unmodified and in full force
and effect; that, to Tenant's knowledge, Tenant has no defenses, offsets or
counterclaims against its obligations to pay the Rent and to perform its other
covenants under this Lease; that to the extent true, there is no default or
Event of Default then existing and Tenant has not received a notice of any
alleged default by Tenant under the Lease; that the Lease has not been modified
or amended (or, if there have been modifications, that this Lease is in full
force and effect as modified and stating the modifications, and, if there are
any defenses, offsets, counterclaims, or defaults, setting them forth in
reasonable detail); the dates to which the Base Rent, Additional Rent and other
charges have been paid; and such other factual
<PAGE>

matters as Landlord may reasonably request. Any such statement delivered
pursuant to this Section 11.8 shall be in a form reasonably acceptable to and
may be relied upon by any prospective purchaser or mortgagee of premises which
include the Premises or any prospective assignee of any such mortgagee.

11.9  WAIVER OF JURY TRIAL.

THE PARTIES HERETO WAIVE TRIAL BY JURY IN ANY ACTION, PROCEEDING OR COUNTERCLAIM
BROUGHT BY ANY PARTY(IES) AGAINST ANY OTHER PARTY(IES) ON ANY MATTER ARISING OUT
OF OR IN ANY WAY CONNECTED WITH THIS AGREEMENT OR THE RELATIONSHIP OF THE
PARTIES CREATED HEREUNDER.

11.10 ACTS OF GOD.

      In any case where either party hereto is required to do any act, delays
caused by or resulting from Acts of God, war, civil commotion, fire, flood or
other casualty, labor difficulties not limited to the Premises or Tenant's or
Landlord's business operations, shortages of labor, materials or equipment,
government regulations, unusually severe weather, or other causes beyond such
party's reasonable control shall not be counted in determining the time during
which work shall be completed, whether such time be designated by a fixed date,
a fixed time or a "reasonable time", and such time shall be deemed to be
extended by the period of such delay.

11.11 BROKERAGE.

      Tenant represents and warrants that it has dealt with no broker in
connection with this transaction other than the Brokers and agrees to defend,
with counsel reasonably approved by Landlord, indemnify and save Landlord
harmless from and against any and all cost, expense or liability for any
compensation, commissions or charges claimed by a broker or agent, other than
the Brokers, with respect to Tenant's dealings in connection with this Lease.
Landlord represents and warrants to Tenant that it has dealt with no broker in
connection with this transaction other than the Brokers and agrees to defend,
with counsel reasonably approved by Tenant, indemnify and save Tenant harmless
from and against any and all cost, expense or liability for any compensation,
commissions or charges claimed by a broker or agent with respect to Landlord's
dealings in connection with this Lease.

11.12 SUBMISSION NOT AN OFFER.

      The submission of a draft of this Lease or a summary of some or all of its
provisions does not constitute an offer to lease or demise the Premises, it
being understood and agreed that neither Landlord nor Tenant shall be legally
bound with respect to the leasing of the Premises
<PAGE>

unless and until this Lease has been executed by both Landlord and Tenant and a
fully executed copy has been delivered to each of them.

11.13 APPLICABLE LAW AND CONSTRUCTION.

      This Lease shall be governed by and construed in accordance with the laws
of the state in which the Premises are located. If any term, covenant, condition
or provision of this Lease or the application thereof to any person or
circumstances shall be declared invalid or unenforceable by the final ruling of
a court of competent jurisdiction having final review, the remaining terms,
covenants, conditions and provisions of this Lease and their application to
persons or circumstances shall not be affected thereby and shall continue to be
enforced and recognized as valid agreements of the parties, and in the place of
such invalid or unenforceable provision, there shall be substituted a like, but
valid and enforceable provision which comports to the findings of the aforesaid
court and most nearly accomplishes the original intention of the parties.

      There are no oral or written agreements between Landlord and Tenant
affecting this Lease, except as specified in this Lease. This Lease may be
amended, and the provisions hereof may be waived or modified, only by
instruments in writing executed by Landlord and Tenant.

      The titles of the several Articles and Sections contained herein are for
convenience only and shall not be considered in construing this Lease,

      Unless repugnant to the context, the words "Landlord" and "Tenant"
appearing in this Lease shall be construed to mean those named above and their
respective heirs, executors, administrators, successors and assigns, and those
claiming through or under them respectively to there be more than one tenant,
the obligations imposed by this Lease upon Tenant shall be joint and several.

11.14 SECURITY DEPOSIT.

Tenant has deposited with Landlord the Security Deposit as security for the
full, faithful and punctual performance by Tenant of all of the terms of this
Lease, whether in cash or by delivery to Landlord of a clean, irrevocable letter
of credit in the amount of the Security Deposit. In the event Tenant defaults in
the performance of any of the terms of this Lease, including the payment of
Rent, Landlord may use, apply or retain the whole or any part of the Security
Deposit to the extent required for the payment of any Rent or for any sum which
Landlord may expend or may be required to expend by reason of Tenant's default
in respect of any of the terms of this Lease, including any damages or
deficiency in the re-letting of the Premises, whether accruing before or after
summary proceedings or other re-entry by Landlord. In the case of every such
use, application or retention, Tenant shall, on demand, pay to Landlord the sum
so used, applied or retained which shall be added to the Security Deposit so
that the same shall be replenished to its former amount and Tenant's failure to
do so shall be a material breach of this Lease. Landlord
<PAGE>

shall not be required to keep such deposit separate from its general accounts
and Tenant shall not be entitled to interest on the Security Deposit. The
Security Deposit shall not be deemed a limitation on Landlord's damages or a
payment of liquidated damages or a payment of the monthly Rent due for the last
month of the Term of this Lease. If Tenant shall fully and punctually comply
with all of the terms of this Lease, the Security Deposit, or so much of it as
has not been applied by Landlord, shall be returned to Tenant, without interest
or other increment for its use, after the termination of this Lease and after
delivery of exclusive possession of the Premises to Landlord. In the event of a
sale or lease of the Building, Landlord shall have the right to transfer the
Security Deposit to the vendee or lessee and Landlord shall immediately be
released by Tenant from all liability for the return of such Security Deposit;
and Tenant agrees to look solely to the new owner or landlord for the return of
said Security Deposit; and it is agreed that the provisions hereof shall apply
to every transfer or assignment made of the Security Deposit to a new owner or
landlord. Tenant shall not assign or encumber or attempt to assign or encumber
the monies deposited herein as the Security Deposit and neither Landlord nor its
successors or assigns shall be bound by any such assignment, encumbrance,
attempted assignment or encumbrance. This Lease does not create a trust
relationship between Landlord and Tenant with respect to such Security Deposit,
and Landlord shall be entitled to treat such Security Deposit as Landlord's own
property, subject only to Tenant's right to receive repayment of it as and to
the extent provided in this Section.

     If the Security Deposit is in the form of an unconditional, irrevocable
letter of credit, such letter of credit shall be issued by a financial
institution acceptable to Landlord and in the form of Exhibit C attached hereto.
                                                      ---------
The letter of credit shall be renewed by Tenant at least 30 days prior to
expiration and shall remain in effect until 90 days after the scheduled end of
the Term of the Lease, as such Term may be renewed or extended. If such letter
of credit is not so renewed at least 30 days prior to expiration, Landlord shall
have the right, without notice to Tenant, to draw the entire amount of such
letter of credit and hold such amount as a cash Security Deposit under the terms
of this Section 11.14. Landlord shall provide written notice to Tenant ,
concurrently with Landlord's notice to the issuer of the letter of credit, that
Landlord is drawing on the letter of credit which notice shall state the amount
being drawn.

11.15 SIGNS.

      Tenant may install, at its sole cost and expense, signs on the exterior of
the Building and on the canopy over the main entrance to the Premises. All
signage must comply with all applicable laws, codes and regulations, including,
without limitation, zoning and building codes. Tenant shall be responsible for
obtaining all necessary permits and approvals. The location, materials, design
and method of installation of all signage shall be subject to Landlord's prior
written approval, which shall not be unreasonably withheld.

                        SIGNATURES FOLLOW ON NEXT PAGE
<PAGE>

      EXECUTED as a sealed instrument in two or more counterparts on the day and
year first above written.

LANDLORD:

BOULDER 38/th/ LLC

By:   Boulder Campus LLC, Manager

      By:   MSC Boulder LLC, Primary Member


            By: /s/ John H. Baxter
                ---------------------------
                Name: John H. Baxter
                Title: Member


TENANT:

GENOMICA CORPORATION


  By: /s/ Dan Hudspeth
      ---------------------------
      Name: Dan Hudspeth
      Title: CFO

<PAGE>

                                   EXHIBIT A
                               PLAN OF PREMISES

                                      A-1
<PAGE>

                                   EXHIBIT B
                                  WORK LETTER


      THIS WORK LETTER AGREEMENT ("Work Letter") is entered into as of the ____
day of _______, 1999 by and between BOULDER 38TH LLC ("Landlord"), and GENOMICA
CORPORATION ("Tenant").

                                   RECITALS

A.    Concurrently with the execution of this Work Letter, Landlord and Tenant
have entered into the Lease covering certain Premises more particularly
described in the Lease. All terms not defined herein have the same meaning as
set forth in the Lease.

B.    In order to induce Tenant to enter into the Lease and in consideration of
the mutual covenants hereinafter contained, Landlord and Tenant agree as
follows:

      1.   LANDLORD'S WORK. As used in the Lease and this Work Letter Agreement,
           ---------------
the term "Landlord's Work" means those items of general tenant improvement
construction shown on the Final Plans (described in Paragraph 4(b) below),
including, but not limited to, partitioning, doors, ceilings, floor coverings,
wall finishes (including paint and wall coverings), electrical (including
lighting, switching, telephones, outlets, etc.), plumbing, heating, ventilating
and air conditioning, fire protection, cabinets and other millwork and
distribution of Building services such as sprinkler and electrical service. All
Landlord's Work and components thereof shall at all times be and remain the sole
property of Landlord. Landlord, at its sole cost, shall erect the walls demising
the Premises, and shall separate the utilities serving the Premises.

      2.   CONSTRUCTION REPRESENTATIVES. Landlord appoints the following
           ----------------------------
person(s) as Landlord's representative ("Landlord's Representative") to act for
Landlord in all matters covered by this Work Letter:

           James M. Halliday
           Great Point Investors LLC
           265 Franklin Street, 18/th/ floor
           Boston, MA 02110
           617.526.8800

and

           Doug McDonald
           Bancroft Capital Advisors, Inc
           1112 Ocean Drive, Suite 300
           Manhattan Beach, CA 90266
           310.318.9120

Tenant appoints the following person(s) as Tenant's representative ("Tenant
Representative") to act for Tenant in all matters covered by this Work Letter.

           Dan Hudspeth, CFO

                                      B-1
<PAGE>

           Genomica Corporation
           ____________________
           ____________________

All communications with respect to the matters covered by this Work Letter are
to be made to Landlord's Representative or Tenant's Representative, as the case
may be, in writing, in compliance with the notice provisions of the Lease.
Either party may change its representative under this Work Letter at any time by
written notice to the other party in compliance with the notice provisions of
the Lease.

      3.   DESIGN AND CONSTRUCTION. All Landlord's Work shall be performed by
           -----------------------
contractors selected and engaged by Landlord. All bids shall be reviewed with
Tenant on an open book basis. Landlord shall engage a registered professional
architect of its choice to design the interior space of the Premises (the
"Architect").

      4.   WORK SCHEDULE. Attached hereto as Schedule 1 is a schedule (the "Work
           -------------                     ----------
Schedule") which sets forth the timetable for the planning and completion of the
installation of the Landlord's Work. The Work Schedule has been approved by both
Landlord and Tenant.

      5.   TENANT IMPROVEMENT PLANS.
           ------------------------

      (a)  Preparation of Final Plans. In accordance with the Work Schedule, the
           --------------------------
Architect will prepare complete architectural plans and complete, fully-
engineered construction drawings and specifications for all of Landlord's Work,
including mechanical, electrical, plumbing and structural elements (collectively
the "Final Plans"). The Final Plans will show: (i) the subdivision (including
partitions and walls), layout, lighting, finish and decoration work (including
carpeting and other floor coverings) for the Premises; (ii) all internal and
external communications and utility facilities which will require the
installation of conduits or other improvements from the base Building shell; and
(iii) all other specifications for Landlord's Work. The Final Plans will be
submitted to Landlord for Landlord's approval and to Tenant for Tenant's
approval. The parties agree to advise each other in writing of any disapproval
of the Final Plans within five business days of receipt thereof. If either party
in its reasonable discretion does not approve the Final Plans, the Architect
will redesign the Final Plans incorporating the revisions reasonably requested.
Within ten business days of submission of the Final Plans, Landlord shall
provide Tenant with a written summary (the "Excess Cost Summary") of the cost of
the Landlord's Work, based on the Final Plans, that is in excess of the Tenant
Improvement Allowance (defined below) ("Excess Costs"). Tenant agrees to advise
Landlord in writing of any disapproval of the Excess Cost Summary, and the
reasons therefor within five business days of receipt thereof. If Tenant fails
to timely deliver to Landlord Tenant's written disapproval of the Excess Cost
Summary, the Excess Cost Summary shall be deemed approved by Tenant. If the
revised Excess Cost Summary is timely disapproved by Tenant pursuant to this
paragraph, Tenant shall provide to Landlord a written explanation of the
reason(s) for such disapproval concurrently with its disapproval, and the Excess
Cost Summary, as appropriate, shall be promptly revised and resubmitted to
Tenant for approval. If Tenant fails to provide a written explanation as and
when required by this paragraph, the Excess Cost Summary shall be deemed
approved by Tenant. Tenant agrees to approve in writing the revised

                                      B-2
<PAGE>

Excess Cost Summary within five business days of its receipt thereof. If Tenant
fails to timely deliver to Landlord written approval of the Excess Cost Summary,
the Excess Cost Summary shall be deemed approved by Tenant. Tenant's approval of
the Excess Cost Summary shall constitute Tenant's agreement to pay Landlord the
Excess Costs.

      (b)  Requirements of the Final Plans. The Final Plans will include
           -------------------------------
locations and complete dimensions, and Landlord's Work, as shown on the Final
Plans, will: (i) be compatible with the Building shell and with the design,
construction and equipment of the Building; (ii) comply with all applicable
laws, ordinances, rules and regulations of all governmental authorities having
jurisdiction, and all applicable insurance regulations; and (iii) be of a nature
and quality consistent with the overall objectives of Landlord for the Building,
as determined by Landlord in its reasonable but subjective discretion.

      (c)  Submittal of Final Plans. Once approved, the Architect will submit
           ------------------------
the Final Plans to the appropriate governmental agencies for plan checking and
the issuance of a building permit. The Architect will make any changes to the
Final Plans which are requested by the applicable governmental authorities to
obtain the building permit. Any changes requested by governmental authorities
will be made only with the prior written approval of Landlord, and only if
Tenant agrees to pay any excess costs resulting from the design and/or
construction of such requested changes (the "Additional Costs"). Landlord shall
revise the Excess Cost Summary by increasing the Excess Costs by the amount of
the Additional Costs resulting from plan modifications required by any
governmental authority. Tenant hereby acknowledges that any such changes will be
subject to the terms of Section 5 below. Any Additional Costs are to be paid by
Tenant to Landlord within ten days after receipt by Tenant of an invoice for
such Additional Costs from Landlord.

      6.   PAYMENT FOR LANDLORD'S WORK.
           ---------------------------

      (a)  Tenant Improvement Allowance and Excess Costs. Landlord shall pay for
           ---------------------------------------------
Landlord's Work up to a maximum of the Tenant Improvement Allowance. The Tenant
Improvement Allowance shall only be used for:

           (i)   Payment to the Architect for all usual space planning, design
           and architectural fees, including, without limitation, all reasonable
           architectural and engineering costs of preparing the Final Plans,
           including mechanical, electrical, plumbing and structural drawings,
           and all other aspects necessary to complete the Final Plans.

           (ii)  Payment of plan check, permit and license fees relating to
           construction of Landlord's Work.

           (iii) Construction of Landlord's Work, including, without limitation,
           the following:

                 (A)  Installation within the Premises of all partitioning,
                 doors, floor coverings, ceilings, wall coverings and painting,
                 millwork and similar items;

                                      B-3
<PAGE>

                 (B)  All electrical wiring, lighting fixtures, outlets and
                 switches, and other electrical work to be installed within the
                 Premises;

                 (C)  The furnishing and installation of all duct work, terminal
                 boxes, diffusers and accessories required for the completion of
                 the heating, ventilation and air conditioning systems within
                 the Premises, including the cost of meter and key control for
                 after-hour air conditioning;

                 (D)  Any additional tenant requirements including, but not
                 limited to, air quality control, special heating, ventilation
                 and air conditioning, noise or vibration control or other
                 special systems;

                 (E)  All fire and life safety control systems such as fire
                 walls, sprinklers, fire alarms, including piping and wiring,
                 installed within the Premises;

                 (F)  All plumbing, including fixtures and pipes, to be
                 installed within the Premises;

                 (G)  Testing and inspection costs; and

                 (H)  Contractor's fees, including, but not limited to, any fees
                 based on general conditions.

           (iv)  All other costs to be reasonably expended by Landlord in the
           construction of Landlord's Work.

      (b)  Changes. If, after the Final Plans and the Excess Costs Summary have
           -------
been approved by Landlord and Tenant, as applicable, Tenant requests any changes
or substitutions to the Final Plans or to Landlord's Work during construction,
Tenant shall complete a change order request form approved by Landlord and
forward it to Landlord's representative. All such changes shall be subject to
Landlord's prior written approval in accordance with Paragraph 11. Prior to
commencing any change, Landlord shall prepare and deliver to Tenant, for
Tenant's approval, a change order setting forth the total cost of such change,
which shall include associated architectural, engineering, construction
contractor's costs and fees, and completion schedule changes. If Tenant fails to
approve such change order within five business days after delivery by Landlord,
Tenant shall be deemed to have withdrawn the proposed change and Landlord shall
not proceed to perform the change. Any additional costs related to such change
are to be paid by Tenant to Landlord within ten days after receipt by Tenant of
an invoice for such additional costs from Landlord.

      (c)  Payment of Excess Costs. Prior to the commencement of Landlord's Work
           -----------------------
and within 10 days of approval, or deemed approval, of the Excess Cost Summary
by Tenant, Tenant shall pay to Landlord the Excess Costs. If the amount of the
Excess Costs changes as a result of a change order, Tenant shall pay such
increased amount within 10 days of receipt by Tenant of an invoice, together
with reasonable supporting documentation, for such increased costs.

      (d)  Credit. Unless specifically set forth herein, Tenant shall not be
           ------
entitled to any credit for any portion of the Tenant Improvement Allowance which
is not used.

                                      B-4
<PAGE>

      7.   CONSTRUCTION OF LANDLORD'S WORK. Until Landlord approves the Final
           -------------------------------
Plans, Tenant approves the Excess Cost Summary and pays the Excess Costs to
Landlord, and all necessary permits have been obtained from the appropriate
governmental authorities, Landlord will be under no obligation to cause the
construction of any of Landlord's Work. Once the foregoing conditions have been
met, Landlord's contractor will commence and diligently proceed with the
construction of the Landlord's Work pursuant to the terms of a [negotiated bid]
contract between Landlord and Landlord's contractor calling for the completion
of Landlord's Work in a good and workmanlike manner conforming to all applicable
Legal Requirements, subject to Tenant Delays (as described in Paragraph 8 below)
and Force Majeure Delays (as described in Paragraph 9 below). The costs of
Landlord's Work shall be paid as provided in Paragraphs 5 and 6 hereof.
Construction inspections will be made periodically by qualified Landlord
employees or subcontractors and Tenant shall have the right to have qualified
Tenant employees or subcontractors review compliance of Landlord's Work with the
Final Plans.

      8.   TENANT DELAYS. For purposes of this Work Letter, "Tenant Delays"
           -------------
means any delay in the completion of the Landlord's Work resulting from any or
all of the following:

      (a)  Tenant's failure to timely perform any of its obligations pursuant to
      this Work Letter, including any failure to approve any item or complete,
      on or before the due date therefor, any action item which is Tenant's
      responsibility pursuant to this Work Letter or the Work Schedule;

      (b)  Change orders requested by Tenant after approval of the Final Plans;

      (c)  Any delay of Tenant in making payment to Landlord for any costs due
      from Tenant under this Work Letter or the Lease; or

      (d)  Any other act or failure to act by Tenant, Tenant's employees,
      agents, architects, independent contractors, consultants and/or any other
      person performing or required to perform services on behalf of Tenant.

      9.   FORCE MAJEURE DELAYS. For purposes of the Work Letter, "Force Majeure
           --------------------
Delays" means any and all causes beyond Landlord's reasonable control,
including, without limitation, delays caused by Tenant, other tenants,
governmental regulation, governmental restriction, strike, labor dispute, riot,
accident, mechanical breakdown, shortages of or inability to obtain labor, fuel,
steam, water, electricity or materials, acts of God, war, enemy action, civil
commotion, fire or other casualty.

      10.  APPROVALS. Whenever any party under this Work Letter must reasonably
           ---------
grant its approval such party shall also not unreasonably delay or condition its
approval. Unless otherwise required by the terms of this Work Letter, any
approval shall be deemed granted unless such party responds within seven days
after its receipt of the items for which approval is sought. Any such request to
the Landlord shall be sent in writing to each of the people listed as the
Landlord's Representative in Section 2 above, provided, however, any approval
needs to be signed by James M. Halliday.

                                      B-5
<PAGE>

      11.  LANDLORD'S APPROVAL. Landlord, in its sole discretion, may withhold
           -------------------
its approval of the Final Plans, change orders or other documents or plans that:

      (a)  Exceeds or adversely affects the structural integrity of the
Building, or any part of the heating, ventilating, air conditioning, plumbing,
mechanical, electrical, communication, or other systems of the Building;

      (b)  Is not approved by any Superior Mortgagee or Superior Lessee at the
time the work is proposed;

      (c)  Would not be approved by a prudent owner of property similar to the
Building;

      (d)  Violates any agreement which affects the Building or the Land or
binds the Landlord;

      (e)  Landlord believes will reduce the market value of the Premises or the
Building at the end of the Term of the Lease; or

      (f)  Does not conform to the applicable building code or is not approved
by any governmental, quasi-governmental, or utility authority with jurisdiction
over the Premises.

      12.  DEFAULTS BY TENANT. In the event of any default by Tenant with
           ------------------
respect to any of the provisions of this Work Letter or any other agreement with
Landlord relating to construction in or about the Premises, Landlord may, in
addition to exercising any other right or remedy Landlord may have, treat such
default as a default by Tenant under the Lease and exercise any or all rights
available under the Lease in connection therewith, including, if applicable, the
right of termination. In the event of any termination of the Lease by Landlord,
Landlord may elect in its absolute discretion, with respect to any work
performed by or on behalf of Tenant prior to the date of such termination, to
either:

      (a)  retain for its own use part or all of any such work, without
      compensation to Tenant therefor; or

      (b)  demolish or remove part or all of any such work and restore part or
      all of the Premises to its condition prior to the initial tender of
      possession thereof to Tenant, in which event Tenant shall reimburse
      Landlord upon demand for all costs reasonably incurred by Landlord in
      connection with such demolition, removal and/or restoration.

                                      B-6
<PAGE>

IN WITNESS WHEREOF, the undersigned Landlord and Tenant have caused this Work
Letter to be duly executed by their duly authorized representatives as of the
date of the Lease.


LANDLORD:

BOULDER 38TH LLC

By:  Boulder Campus LLC, Manager

     By:  MSC Boulder LLC, Primary Member


          By: __________________________
              Name:
              Title:


TENANT:

GENOMICA CORPORATION


By: __________________________
    Name:
    Title:

                                      B-7
<PAGE>

                                  Schedule 1

                                 Work Schedule

                                      B-8
<PAGE>

                                   EXHIBIT C

                            [On Bank's Letterhead]

                         IRREVOCABLE LETTER OF CREDIT



                                                  _____________, 1999


Irrevocable Letter of Credit No._________


Beneficiary
-----------


Boulder 38/th/ LLC
c/o Great Point Investors LLC
265 Franklin Street, 18/th/ floor
Boston, MA 02110
Attn: John H. Baxter

Applicant
---------
[TENANT NAME AND ADDRESS]

Expiration Date:  ____________________
---------------

Ladies and Gentlemen:

_________________________ ("Issuer") hereby issues our unconditional and
irrevocable Letter of Credit No._______ in Beneficiary's favor in the amount of
_____________________ U.S. Dollars ($_______________) available by your sight
drafts drawn on us and accompanied by a written statement signed on behalf of
Boulder 38/th/ LLC, its successors or assigns, stating as follows:

      "The undersigned certifies that Boulder 38/th/ LLC and/or its successors
      and assigns is entitled to draw under the Irrevocable Letter of Credit
      No.______ pursuant to the terms of a Lease, dated ___________, 1999,
      between Boulder 38/th/ LLC and _________________________."


Partial drawings are permitted.

We engage with you that all drafts drawn under and in compliance with the terms
of this Irrevocable Letter of Credit will be duly honored if presented to us on
or before the expiration date set forth above.  Any draft drawn by you under
this Irrevocable Letter of Credit must bear the clause "Drawn on Irrevocable
Letter of Credit No. _______ of _____________________".

                                      C-1
<PAGE>

It is a condition of this Irrevocable Letter of Credit that it shall be deemed
automatically extended without amendment for additional successive one year
periods from the expiration date hereof, or any future expiration date, unless
60 days prior to any expiration date we notify you by certified mail, return
receipt requested or overnight courier that we elect not to consider this
Irrevocable Letter of Credit renewed for any such additional period.

This Irrevocable Letter of Credit is fully transferable and assignable by
Beneficiary. Beneficiary shall send a written request to Issuer to assign or
transfer this Irrevocable Letter of Credit and upon presentation of this
Irrevocable Letter of Credit, as it may be amended, to Issuer, Issuer shall re-
issue this Irrevocable Letter of Credit in the then outstanding amount in favor
of Beneficiary's successor, assign or transferee. Any subsequent successor,
assignee or transferee of this Letter of Credit may also assign this Letter of
Credit as provided for herein.

Partial drawings and reductions are permitted.

This Irrevocable Letter of Credit sets forth in full the terms of our
undertaking, and such undertaking shall not in any way be limited, modified,
amended or amplified, except by a written document executed by the parties
hereto.

Except as otherwise expressly stated herein, this Irrevocable Letter of Credit
is subject to the Uniform Customs and Practices for Documentary Credits (1993
Revision), International Chamber of Commerce Publication No. 500.

Very truly yours,

____________________________


By:________________________
   Name:
   Title:

                                      C-1