April 2, 1973

Dr. Tetsuo Line
Laboratory of Genetics
Faculty of Science
University of Tokyo
Hongo, Tokyo 113, JAPAN

Dear Tetsuo,

I just wanted to call your attention to the way that cyclic AMP is

appearing almost everywhere as a regulator in microbial as well as
eukaryotic systema.

Specifically I wanted to Suggest that you look into it as a possible
factor in (1) the inhibition of Hy expression by the Hj product and
(2) the "mutatéon" at Ah.

Some references below.

All best wishes,

Joshua Lederberg
Professor of Genetics

P.&. Did you see Sgaramella's paper in PNAS 10/32? We have some exciting
follow-up on that now, initiating a reasonable transfection system

with P22 DNA. But not yet to the efficiency where we can demonstrate
bacterial transfer with DNA.

\
JL/rr priya:

Enclosure (References)