UNIVERSITY OF WASHINGTON 
SEATTLE, WASHINGTON 9819S 
Department of Biochemistry f SJ-70 
August 28, 1978 
Dr. D. S. Fredrickson, 
Director 
National Institutes of Health 
Bethesda, MD 20014 
Dear Dr. Fredrickson: 
I am writing this letter to urge your consideration in adding Caulobacter 
creecentue to the list of organisms which are exempt from the NIH Recombinant 
DNA guidelines. 
I have been in contact with Dr. Bert Ely regarding this matter, since his 
laboratory is primarily concerned with the development of the Caulobacter 
genetic system. It has been my understanding that the efficient intergeneric 
transfer of genetic material under "optimal laboratory conditions" has been 
demonstrated in Caulobacter. Transfer of RP1 to C. creecentue was initially 
demonstrated by Alexander and Jollick (1977) and Dr. Ely and his laboratory 
have demonstrated the transfer of other P-type plasmids and colEl to 
C. creecentue . Dr. Ely has also provided me with a preprint of a manuscript 
submitted to Genetice which provides well-documented evidence of: 
1. the transfer of RP4, RK2, R68.45, R702 and R46 from E. coli to 
C. creecentue ; 
2. expression of drug resistance to tetracycline and kanamycin mediated 
by RP4. Additional evidence of RP4 expression in C. creecentue was provided 
by the demonstration that C. creecentue containing RP4 produce RP4-type pili 
and are subsequently sensitive to RP4 sex pilus-dependent phage; 
3. RP4 mobilization of colEl transfer to C. creecentue . However, 
ColEl in C. creecentue can be maintained and expressed in the absence of RP4; 
4. RP4 mobilization of chromosome transfer between C. creecentue and 
E. coli (either direction); 
5. the insertion of transposable element Tn 7 in the C. creecentue 
chromosome. 
[A-55] 
J405 Health Sciences Building, SJ-70 / Telephone: (206) 543-1660 
