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THE COUNCIL FOR TOBACCO I:ESEARCH--U.S.A., INC. 900 TIIIRD AVENUE NEW YORK. N. Y. 10022 Memwrandtan: To: Dr. H. McAllister and Staff Fran: D.H. Ford Re: Site visit with Dr.Colin Jefcoate, University of Wisccnsin, Madison,WI. July 20, 1993. Grant No. 2963A entitled "Physiology of a Farnily of Novel p450 Cyto:hranes." This represents a slight change in title, which was previaxsly "Control of Two Novel Rodent p450 Cytochranes." Aims: As currently stated: 1. Identify cell regulatcry mechanisms that alter p450B in embryo fibrcblasts and determine to what extent these are cell specific. 2. Determine the specificity of expressicn of p450B in rodent fibroblasts and epitheLial cells in the uterus, prostate, kidney, lung, skin, and etc. 3. Identify DNA sequence elements binding cell-specific regulatory factors. These gcals appear to represent a logical evoluticn of his original studies with p450-EF and RAP. A long-tenn goal is to determine haa strcmal fibrcblasts signal epithelial cells. He believes that p450B or sane other menber of the p450 family may be the signalling factor. Further, the fibrcblasts with which Dr. Jefcoate is ccncerned appear to be those which are sensitive to steroids. Thus, he is also focussing cn the hcrmonal regulaticn of p450s in steroid sensitive tissues. Results: See Dr. Jefcoate's progress report sutxliitted with his 2963 applicaticn. He has isolated a cDNA which recognizes a 5. 2"'(maj or) and a 4.3 kb (minor) R,IA in rat adrena ls (ACTH induced) and in 10T1 /2 ce lls ( 2, 3, 7, 8-tetrachlcrodibenz edi c~cin and benz(a)anthraeene) induced. The amino terminal sequence and faar internal peptides were abtained by lysopeptidase digesticn of p450RAP._Where sequencing has been canpl,eted, there is oonsiderable hanology between mouse and rat sequences and the p450RAP protein sequence. Dr. Jefcoate has confirnned his belief that p450-EE' is the first nenber (at least that he has recognized) of a new family of p450 cytodzranes which appears to be expressed in mice, rats, hamsters and humalLs (and perhaps others) in tissues which are respcnsive to steroids. While imnunologically different fran p450 lAl, the p450- EF also appears to be regulated by the AH-receptcr. His data suggest that proteins of the p450-EF family are important in relaticrl to polycyc]ic hydrocarbrn-induced toxicity and cancer in endocrine tissues with the possibility that there may be mutagenic effects in the ovary and testes. Calgne.nt:An interesting program with cbvicus significance in rel.atial to the role of p450s in the evoluticrl of cancer, particularly in tissues which are ster.md hmnone sensitive and which have fibroalasts in their strana which are endaved with p450-EF or perhaps some other member of this new falni.ly of p450s. DHF