Original Repository: Stanford University Libraries. Department of Special Collections and University Archives. Paul Berg Papers
Reproduced with permission of Paul Berg.
Medical Subject Headings (MeSH):
Molecular Biology and a Changing Academic Landscape, 1980-present
Letter from Marianne Grunberg-Manago to Paul Berg (May 10, 1979)
Letter from Paul Berg to Marianne Grunberg-Manago (June 8, 1979)
July 5, 1979
This is a follow-up to the letter I sent awhile back about the translation of the globin sequence in SV40. I enclose a copy
of the paper given at the ICN Conference last March.
The result with SVGT5-beta-G is not unexpected; we assume but should test that beta-G is being made off the smaller mRNA and
not off the larger one (that is the case for the natural coding sequence VP1). The result with SVGT9-beta-G is also consistent
with the expectation that translation occurs only from the first AUG after the leader sequence but other experiments are needed
to determine if any translation starts at the internal beta-G AUG; we expect no globin is made from the larger mRNA. The paradox
comes from the recombinant SVGT7-beta-G. Here we expect only one class of mRNA, the large one, although the large mRNA may
actually be a family of mRNAs some of which have the splice in front of the first AUG (as shown in Fig. 4) and others with
the splice behind the first AUG so as to make the second AUG (the one coding for VP3) the first one after the leader. In either
case we would not have expected the beta globin sequence in either mRNA to be translated. Yet beta-globin is clearly made.
Moreover, we do find a new small mRNA containing the globin sequence and a bit of leader sequence. According to all we know
there is normally no splice from the leader to a position behind the second AUG but maybe under certain conditions that does
occur. If it does then the formation of beta-globin from such a mRNA would not violate the Jacobson-Baltimore rule. We are
doing further experiments to characterize this mRNA and also to produce other kinds of recombinant where the beta-globin AUG
is or is not the first from the cap. Those answers will be along soon.
I thought we would have an answer about whether recombinants in which various parts of the 5' - noncoding region of the
beta-globin cDNA have been deleted (by Charles Weissmann) still make globin. But those recombinants are still being grown
or characterized and the infections have not yet been done. When that information is available I'll send it along.
Hope all is well with you and the family. Have a good Summer.