THE CDNA CLONING AND TRANSIENT EXPRESSION OF A CHICKEN GENE ENCODING CYTOCHROME P-450SCC

A cDNA clone, pcSCC1, isolated from a chicken adrenal gland library sh owed about 62% nucleotide sequence similarity to those of mammalian an d rainbow trout P-450scc cDNAs and was proved to be the clone for chic ken P-450scc by the enzymatic activity of converting 25-hydroxycholest erol to pregnenolone demonstrated in the transfected COS-7 cells. Comp arison of deduced amino acid sequences shows significant conservation of heme- and steroid-binding domains but little similarity in the puta tive N-terminal presequence region among chicken, trout and mammals. T he chicken cDNA lacks a polyadenylation signal in its 3'-UTR . Sequenc ing of a 3' end region of the P-450scc gene (CYP11A1) suggests that a region containing the polyadenylation signal is spliced out from the p re-mRNA.