UNIVERSITY OF CALIFORNIA, SAN FRANCISCO

BFSELEY - DAVIS * IRVINE * LOS ANGELES o RIVERSIDE * SAN DIEGO - SAN FRANCISCO

SANTA BARBARA * SANTA CRUZ

SCHOOL OF MEDICINE
Department of Microhiology
  and Immunology

SAN FRANCISCO. CALIFORNIA 94143

June 17, 1983

Dr. Robert Weinberg
Massachusetts Institute

Department of Cell Biology
Center for Cancer Research
Cambridge, MA. 02139

of Technology

Dear Bob:

   I enjoyed your recent visit here and think our symposium was a great  hit.
Since your departure I've had many conversations about the recent work on  com-
plementation assays in your lab, and we have given some serious thought to the
kinds of things we should send to you.
firm decision about some of these reagents may reflect a misguided ambition on
the part of some of us here to consider setting up the complementation assay to
exploit some of the more specialized reagents we have on hand. Furthermore,
some of these reagents were made at some considerable effort and represent
unique materials yet to be fully reported. Let me run down the list and perhaps
we can talk on the telephone about your feelings about each of these items.

Part of the difficulty in coming to a

      (1) I have talked to Roe1 in Amsterdam and he intends to attempt to try
   transformation assays with new clones of the E-1 locus linked to proviruses
  , more appropriately positioned in the z-1 locus than in the clones currently
. ' \ available. I believe appropriate clones could be Made from the available ma-
   terials simply by adding retroviral or SV40 regulatory regions to clones that

t,

contain what we believe to be the entire - int-1 transcriptional unit.  I would be
willing to consider making these here. Alternatively, we would be happy to send
the w-1 lambda clones from the normal mouse library.  These would probably not
be expressed unless a promoter or enhancer were introduced.

f2f We have, as 1 mentioned, plasmids in which the v-E gene is under the

control of the MMTV LTR. These plasmids contain enhancer sequences and the con-
stitutive level is sufficiently high in most of our transformed cells to cause
morphological transformation without anchorage independence.  These clones un-
dergo 4- to 5-fold induction of     in the presence of dexamethasone resulting
in anchorage independence.
er sequences of E and are likely to have lower constitutive levels of expres-
sion, but these have not yet been tested directly.  As you know, we have yet to
describe the construction of the dexamethasone-regulated viral gene, but we
would certainly be willing to discuss further the possibility of sending you ei-
ther of the two described plasmids.

We have also made similar plasmids that lack enhanc-

  (3) As you know, Richard Parker has e-= under the control of SV40,
resulting in efficient expression. He is mulling over the question of whether
he would like to consider setting up this kind of assay when he arrives at
Columbia, or whether he should offer you that reagent.

-2-

(4) We have a potentially interesting c-myc clone that you might want to

consider for further testing.
gene in a locus containing a provirus positioned backwards and upstream, and has
found that somatic mutations must have occurred in the coding sequence because a
- Sac I site has been altered in an allele which contains the Sac I site in the
germ line of the same animal.  It might be worthwhile to consider testing the
locus cloned from this tumor with and without the substitution of an unaltered
c-Q coding domain.

Dave Westaway has sequenced part of the c-Q

(5) Lastly, I gather from conversations with Manfred that he is preparing

to send you a clone of the N-E gene, the =-related gene that is amplified in
neuroblastomas.

I hope this isn't all too complicated, and that we can soon have some use-

ful materials flowing in your direction. 1'11 be out of town next week, but
perhaps you can give me a call the week of the 27th to discuss these things
further.

I note, by the way, that you will be coincident with me in Paris. Let me

recommend Hotel Saint-Simon, 14, rue de Saint-Simon. 1'11 be staying there from
the 7th to the 10th of September and, as you know, my taste in hotels is in-
disputable.

Look forward to seeing you soon,

Harold E. Varmus, M.D.
Professor

HEV/ jm