title: Cloned cytochrome P-450 cDNA. Nucleotide sequence and homology to multiple phenobarbital-induced mRNA species.
abstract: Phenobarbital (PB) treatment of rats of various strains leads to the accumulation of liver mRNAs which encode two or three immunochemically related but electrophoretically separable cytochrome P-450 polypeptides. These mRNAs hybridize efficiently to a single cloned cDNA derived from mRNA of PB-treated rats and, therefore, must have extensive sequence homology. The nucleotide sequence of this cloned cDNA was determined and shown to encode the COOH-terminal 211 amino acids of one of the major cytochrome P-450 isozymes induced in rat liver by PB. Together with the recently reported sequence data of Fujii-Kuriyama et al. (Fujii-Kuriyama, Y., Mizukami, Y., Kawajiri, K., Sagawa, K., and Muramatsu, M. (1982) Proc. Natl. Acad. Sci. U. S. A. 79, 2793-2797) for cloned rat cytochrome P-450 cDNA, our data suggest that differences between two closely related P-450 isozymes are restricted to the COOH-terminal half of the polypeptides, with highly divergent regions flanking a tridecapeptide which has been previously shown to be highly conserved in two dissimilar forms of rabbit liver cytochrome P-450. The significance of other interesting features of the cDNA sequence such as a second long (409 residues) open frame, an unusual poly(A) addition signal, and the absence of long hydrophobic stretches in the encoded polypeptide is discussed.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D004247:DNA / Q000032:analysis*; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D008297:Male; D010634:Phenobarbital / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats
chemical_list: D012333:RNA, Messenger; D004247:DNA; D003577:Cytochrome P-450 Enzyme System; D010634:Phenobarbital