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                                                                    EXHIBIT 10.6



                         ZFP CUSTOM SYNTHESIS AGREEMENT


        THIS ZFP CUSTOM SYNTHESIS AGREEMENT dated as of ___________, 1999 (the
"Agreement"), is entered into between SANGAMO BIOSCIENCES, INC., a Delaware
corporation ("Sangamo"), having a place of business at Point Richmond Tech
Center, 501 Canal Boulevard, Suite A100, Richmond, California 94804, and
_____________________________, a ____________ corporation (the "Customer"),
having a place of business at ____________________.

        WHEREAS, Sangamo has rights and expertise regarding the design and
synthesis of certain zinc finger DNA recognition proteins and genes encoding
such proteins.

        WHEREAS, the Customer desires to have Sangamo design, assemble,
characterize and deliver to Customer certain of these materials solely for the
Customer's own internal research and preclinical development purposes on the
terms and conditions set forth in this Agreement.

        NOW, THEREFORE, in consideration of the foregoing premises and the
mutual covenants set forth below, the parties agree as follows:

        I. Definitions. For purposes of this Agreement, the terms defined in
this Section 1 shall have the respective meanings set forth below:

               1.1 "Affiliate" shall mean, with respect to any Person, any other
Person which directly or indirectly controls, is controlled by, or is under
common control with, such Person. A Person shall be in control of another Person
if it owns, or directly or indirectly controls, at least fifty percent (50%) of
the voting stock or other ownership interest of the other Person, or if it
directly or indirectly possesses the power to direct or cause the direction of
the management and policies of the other Person by any means.

               1.2 "Confidential Information" shall mean, with respect to a
party, all information (and all tangible and intangible embodiments thereof)
which is disclosed by such party to the other party and is marked, identified as
or otherwise acknowledged to be confidential at the time of disclosure to the
other party. Notwithstanding the foregoing, Confidential Information of a party
shall not include information which the other party can establish by written
documentation (a) to have been publicly known prior to disclosure of such
information by the disclosing party to the other party, (b) to have become
publicly known, without the fault of the other party, subsequent to disclosure
of such information by the disclosing party to the other party, (c) to have been
received by the other party at any time from a source, other than the disclosing
party, rightfully having possession of and the right to disclose such
information, (d) to have been otherwise known by the other party prior to
disclosure of such information by the disclosing party to the other party, or
(e) to have been independently developed by employees or agents of the other
party without access to or use of such information disclosed by the disclosing
party to the other party.


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               1.3 "Derivative" shall mean any protein or conjugate (including a
conjugate to a functional domain other than the Functional Domain) derived from
a ZFP, provided that the contiguous amino acid sequence of such ZFP has not been
altered, and the amino acid sequence of such protein or conjugate.

               1.4 "Functional Domain" shall mean the functional domain set
forth on Schedule A, to which each ZFP shall be conjugated by Sangamo hereunder.

               1.5 "Genetic Material" shall mean, with respect to any ZFP or
Derivative, the nucleotide sequence encoding such ZFP or Derivative and all
fragments of such gene sequence.

               1.6 "Person" shall mean an individual, corporation, partnership,
limited liability company, trust, business trust, association, joint stock
company, joint venture, pool, syndicate, sole proprietorship, unincorporated
organization, governmental authority or any other form of entity not
specifically listed herein.

               1.7 "Research Field" shall mean the research and preclinical
development of products and services for use in the diagnosis, prevention or
treatment of any disease, state or condition in humans (excluding products and
services that incorporate, contain or use zinc finger DNA recognition proteins,
genes that encode such proteins, or progeny, fragments or derivatives of such
proteins or genes).

               1.8 "Target" shall mean the nucleotide sequence set forth on
Schedule A.

               1.9 "ZFP" shall mean a zinc finger DNA recognition protein
binding to the Target which is designed by Sangamo and for which the Genetic
Material is delivered to the Customer hereunder, and the amino acid sequence of
such protein.

               1.10 "ZFP Materials" shall mean, collectively, the ZFPs, any
Derivatives, the Genetic Materials which encode any ZFP or Derivative, and all
progeny, fragments and derivatives of the foregoing.

        2. Design and Delivery of ZFP Materials.

               2.1 Promptly after the date of this Agreement, the Customer shall
deliver to Sangamo the nucleotide sequence for the Target and such other
information as the parties mutually agree is reasonably necessary to assist
Sangamo in designing the ZFPs.

               2.2 Sangamo shall design, assemble and characterize two (2) zinc
finger DNA recognition proteins binding to the Target.

               2.3 Within ten to sixteen (10-16) weeks after receipt of the
information described in Section 2.1 above, Sangamo shall sell and deliver to
the Customer the Genetic Material which encodes each ZFP conjugated to the
Functional Domain, and shall deliver to the Customer certain information
regarding the characterization of each ZFP (including data regarding the binding
sites and affinities) that is reasonably necessary for the Customer to use the
ZFP Materials in the Research Field.


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               2.4 Within twenty (20) days after delivery of the Target to
Sangamo, the Customer shall pay Sangamo (one-half of the total amount) (US
$_____). Such payment shall be in United States Dollars in immediately available
funds and shall be made by wire transfer from a United States bank located in
the United States to such bank account as designated by Sangamo to the Customer.

                      Within twenty (20) days after Sangamo delivers to the
Customer the Genetic Materials and information described in Section 2.3 above,
the Customer shall pay to Sangamo (the remaining one-half of the total amount)
(US $_____). Such payment shall be in United States Dollars in immediately
available funds and shall be made by wire transfer from a United States bank
located in the United States to such bank account as designated by Sangamo to
the Customer.

        3. Use of ZFP Materials.

               3.1 The Customer shall use the ZFP Materials (and all results of
its activities in the Research Field hereunder) solely in the Research Field,
and not for any other purpose.

               3.2 The Customer shall not alter the nucleotide sequence or amino
acid sequence of, or reverse engineer, the ZFP Materials; provided, however,
that the Customer may make Derivatives of the ZFPs.

               3.3 The Customer shall use the ZFP Materials under commercially
and scientifically reasonable containment conditions. The Customer shall not
transfer or provide access to the ZFP Materials to any other Person.
Notwithstanding the foregoing, the Customer may transfer the ZFP Materials to an
Affiliate (without the further right to transfer), provided (a) the Customer
shall give prior express written notice thereof to Sangamo, and (b) such
Affiliate agrees to be bound by the terms and conditions set forth in this
Agreement binding on the Customer. The Customer shall limit access to the ZFP
Materials to those of its employees and consultants working on its premises to
the extent such access is reasonably necessary to the conduct of its activities
in the Research Field.

               3.4 The Customer shall not (and shall not attempt or purport to)
sell, license or otherwise transfer title to or an interest in, or otherwise
commercially use the ZFP Materials without the prior express written consent of
Sangamo.

               3.5 The Customer acknowledges that the ZFP Materials are
experimental in nature, may have unknown characteristics and have not been
approved for use in humans. The Customer shall use prudence and reasonable care
in the use, handling, storage, transportation, disposition and containment of
the ZFP Materials, and shall comply with all applicable laws, regulations and
guidelines applicable to the ZFP Materials or the use thereof and with any
safety precautions accompanying the ZFP Materials. The Customer shall not (and
shall not attempt or purport to) administer the ZFP Materials to humans, or file
or submit any regulatory application or other submission to obtain approval
therefor.

        4. Non-Assertion. Neither the Customer nor its Affiliates (nor their
respective successors, assigns, licensees or other transferees) shall enforce
(or attempt or purport to enforce) against Sangamo or its Affiliates, licensees
(of rights in zinc finger DNA recognition proteins) or manufacturers,
distributors or other purchasers (of zinc finger DNA recognition proteins) any


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patent that claims the ZFP Materials or the use thereof (except that this
Section 4 shall not apply to patents that claim the use of any composition that
binds to a Target(s) for the purpose of diagnosing, treating or preventing a
human disease, state or condition).

        5. No Prohibition on Sangamo. Nothing in this Agreement shall prohibit
Sangamo from making, using, offering for sale, selling to others or importing
zinc finger DNA recognition proteins, genetic materials encoding such proteins,
fragments of such proteins or genetic materials or from licensing others to do
the same; provided, however, that Sangamo shall not design, assemble,
characterize and deliver to any other Person any zinc finger DNA recognition
protein binding to the Target (or genetic material encoding such protein) in
less time than the time frame then published by Sangamo for its custom design,
assembly, characterization and delivery of a zinc finger DNA recognition protein
(or genetic material encoding such protein) generally.

        6. NO REPRESENTATIONS. THE CUSTOMER ACKNOWLEDGES THAT THE ZFP MATERIALS
ARE PROVIDED "AS IS" AND THAT SANGAMO MAKES NO REPRESENTATIONS OR WARRANTIES,
EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED WARRANTY OF
MERCHANTABILITY, FITNESS FOR ANY PARTICULAR PURPOSE OR NONINFRINGEMENT OF THE
PATENT RIGHTS OR OTHER INTELLECTUAL PROPERTY RIGHTS OF ANY OTHER PERSON.

        7. Confidentiality.

               7.1 For a period of five (5) years following the date of this
Agreement, each party shall maintain in confidence all Confidential Information
disclosed by the other party, and shall not use, disclose or grant the use of
the Confidential Information except on a need-to-know basis to its directors,
officers, employees and consultants to the extent such disclosure is reasonably
necessary in connection with such party's activities expressly authorized by
this Agreement and ordinary business operations. Each party shall notify the
other promptly upon discovery of any unauthorized use or disclosure of the other
party's Confidential Information.

               7.2 Sangamo shall not disclose the identity of the Target to any
other Person without the prior consent of the Customer. Neither party shall
disclose any terms or conditions set forth in this Agreement to any other Person
without the prior consent of the other party; provided, however, that a party
may disclose the terms or conditions set forth in this Agreement, (a) on a
need-to-know basis to its legal and financial advisors to the extent such
disclosure is reasonably necessary in connection with such party's activities as
expressly permitted by this Agreement, and (b) to a third party in connection
with (i) an equity investment in such party, (ii) a merger, consolidation or
similar transaction by such party, or (iii) the sale of all or substantially all
of the assets of such party. Notwithstanding the foregoing, prior to execution
of this Agreement, the parties have agreed upon the substance of information
that can be used to describe the terms and conditions of this transaction, and
each party may disclose such information, as modified by mutual written
agreement the parties, without the consent of the other party.

               7.3 The confidentiality obligations contained in this Section 7
shall not apply to the extent information is required to be disclosed to a
governmental agency or is necessary to file or prosecute patent applications or
to the extent that a party is required to disclose information by applicable
law, regulation or order of a court of competent jurisdiction, provided that
such party shall provide written notice to the other party and sufficient
opportunity to object to any


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such disclosure or to request confidential treatment. The Customer may disclose
Confidential Information of Sangamo relating to the results of the Customer's
research and preclinical development hereunder to any Affiliate.

               7.4 To the extent that a party is authorized by this Agreement to
disclose Confidential Information of the other party to any other Person, prior
to disclosure, such party shall obtain agreement of any such Person to hold in
confidence and not use the Confidential Information of the other party for any
purpose other than those permitted by this Agreement.

        8. Indemnification and Insurance.

               8.1 The Customer shall indemnify and hold harmless Sangamo from
and against all losses, liabilities, damages and expenses (including reasonable
attorneys' fees and costs) resulting from all claims, demands, actions and other
proceedings by any other Person to the extent arising from (a) the use by
Sangamo of the Target under this Agreement, (b) the breach by the Customer of
any covenant under this Agreement, or (c) the use by the Customer or its
Affiliates of the ZFP Materials or the results of their respective activities
hereunder, except in each case to the extent any such loss, liability, damage or
expense results from the gross negligence or willful misconduct of Sangamo.

               8.2 The Customer shall maintain such liability insurance covering
its activities contemplated by this Agreement in such amounts and with such
carriers as is customary in the industry regarding similar activities, provided
that such amounts are not less than the amounts which it customarily maintains
covering its similar activities.

               8.3 EXCEPT AS OTHERWISE SET FORTH IN THIS SECTION 8, IN NO EVENT
SHALL EITHER PARTY BE LIABLE FOR LOSS OF PROFITS OR INCIDENTAL, SPECIAL,
CONSEQUENTIAL OR PUNITIVE DAMAGES OF THE OTHER PARTY DIRECTLY OR INDIRECTLY
ARISING OUT OF THIS AGREEMENT.

        9. Miscellaneous.

               9.1 This Agreement shall be governed by and construed in
accordance with the laws of the State of California, without regard to the
conflicts of law principles thereof.

               9.2 This Agreement does not grant to the Customer any license or
other right in the patent rights or other intellectual property rights of
Sangamo except and only to the extent necessary to enable the Customer to
conduct its internal research and preclinical development permitted hereby.

               9.3 For the period from the date of this Agreement through the
date that is one (1) year after the date Sangamo delivers to the Customer the
ZFP Materials and information under Section 2.3 above, neither the Customer nor
its Affiliates shall directly or indirectly solicit or in any manner encourage
any employee of Sangamo to leave its employ.

               9.4 The Customer shall not assign or otherwise transfer (whether
voluntarily, by operation of law or otherwise) this Agreement or any right or
obligation hereunder, without the prior express written consent of Sangamo;
provided, however, the Customer may, without such consent, assign this Agreement
and its rights and obligations hereunder in connection with the


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transfer or sale of all or substantially all of its business, or in the event of
its merger, consolidation, change in control or similar transaction. Any
permitted assignee shall assume all obligations of its assignor under this
Agreement. Any purported assignment or transfer in violation of this Section 9.4
shall be void.

               9.5 This Agreement contains the entire understanding of the
parties regarding the subject matter hereof. All express or implied
representations, agreements and understandings, either oral or written,
heretofore made are expressly superseded by this Agreement.

        IN WITNESS WHEREOF, the parties have entered into the Agreement
effective as of the date first written above.


                                        SANGAMO BIOSCIENCES, INC.


                                        By:

                                        Title:


                                        -----------------------------


                                        By:

                                        Title:


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                                   SCHEDULE A

                          TARGET AND FUNCTIONAL DOMAIN


                                [TO BE COMPLETED]