Original Repository: Stanford University Libraries. Department of Special Collections and University Archives. Paul Berg Papers
Reproduced with permission of Julian B. Fleischman.
Medical Subject Headings (MeSH):
Protein Synthesis, Tumor Viruses, and Recombinant DNA, 1959-1975
Letter from Paul Berg to Julian B. Fleischman (November 27, 1962)
23 novembre 1962
Mel mentioned that you have a method of assaying DNA polymerase activity in crude coli extracts by measuring incorporation
of a labeled ribonucleoside triphosphate in the presence of three other deoxyribonucleotide triphosphates. If this is feasible,
I would be most grateful if you would send me the details. Jean-Marie has prepared some labelled ribonucleoside triphosphates
which could be used as substrates.
We are trying to screen a large number of temperature-sensitive mutant strains (i.e. strains which won't grow at 42 degrees
C) for possible inactivation of DNA polymerase at this temperature. We have selected a number which, on the basis of thymidine
and P32 incorporation, seem to be unable to synthesize DNA at 42 degrees. We would therefore like to set up a convenient in
vitro assay for polymerase activity, preferably in crude extracts, so details of your method, or any other suggestions, would
be most welcome.
Es has probably reported all the activity going on here at present. The only change is that the weather has turned thoroughly
lousy. In spite of Paris, I still miss Palo Alto.