Department of Microbiology and * Lolow
Dr. Anthony L. Schincariol

Duke University Medical Center
Durham, North Carolina 27710

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Dear Dr. Schincariolt

I am abut to submit for publication a manuscript which describes some of our re-
cent efforts to study RSV-specific DHA in normal and infected chicken cells.
most respects, our data are consistent with those presented in your recent report
(Viroloay 56:532, 1973).
to us.
chick cells.
result could be taken to mean that virtually ell of the RSV genome is present in
normal cells.
RSV's means that a large fraction of the RSV genome should hybridiee to normal cell
DNA, but the issue of whether my
are added during infection is critical to attempts to decide the validity of the
oncogene hypathesis.
of' B77 cDIVA to normal chick DHA; both the rate and extent of annealing increase after
infection,  If the cDNA is repeatedly incubated with very large excesses of normal
chick embryo DNA, as much as SO%, but no more, anneals.
able fraction of the remaining unannealed cDNA will, however, anneal WLth DNA from
B77-transformed chick cells, prompting u8 to argue that sequences absent from normal
cells are added during infection.
of course, remains to be determined.

In

However, there is one discrepancy which is of some interest

In Figure 10 you show 95% annealing of your PrC cDHA to DNA from hinfected

Since your cIXA is relatively representative of the RSV genome, this

Surely the extensive homology (60-70X) between MV-0 and genomes of

           sequences (particularly oncogenic sequencesi

We find in experiment8 similar to yours, only about 30% annealing

At this point, a consider-

Whether these sequences code for oncogenic functions,

In view of our results - and the temptation I have experienced to plot the data as a
fraction of maximal. annealinq 1 rather than raw fraction hybridized) - I wander whexher
you made any such correction in polting your data.

in the hybridizationpprobes, unless you have some more interesting ides.

                                      If not, I suppose we can alwaya
&+L wppbss- that these differences in our reeults ma~r be due to sequence representation

Incidentally, I thought your paper was extremely pretty.
of our less elegant manuscript.

I will send you a preprint

Harold E. Varmus, M.D.
Assistant Professor
Department of Microbiology

HEV : bb