Structural and evolutionary studies on sterol 14-demethylase P450 (CYP51), the most conserved P450 monooxygenase: I. Structural analyses of the gene and multiple sizes of mRNA.
The structure of rat CYP51 gene encoding sterol 14-demethylase was examined. The CYP51 gene spanned about 18 kb and contained 10 exons. The copy number of CYP51 in the rat genome was determined to be one. In addition, one CYP51 processed (intron-less) pseudogene covering the coding and ca. 600-bp 3'-noncoding sequences of CYP51 cDNA was found in the rat genome. Multiple transcription initiation sites were predicted by primer extension and 5'-RACE methods using poly(A)+ RNA from liver, ovary, and testis, and the major ones were located at 126 and 123 nucleotides upstream from the initiation ATG codon. The primer extension also showed several minor sites around the major ones. In addition to these sites, other minor initiation sites were also predicted at around 330 and 460 nucleotides upstream from the initiation ATG codon. No TATA box was found in the putative promoter region, but multiple GC boxes were found around the cap sites, supporting the previously inferred housekeeping nature of CYP51 gene and the existence of the multiple transcription initiation sites. A few consensus transcription regulatory elements such as CRE were found in the 5'-flanking region. Four polyadenylation signals were found in the 3'-noncoding region by the 3'-RACE method. Three of them were used to generate 3.1-, 2.7-, and 2.3-kb mRNAs in liver and ovary. The remaining one was used only in testis to generate 1.9-kb mRNA having an unusually short trailer sequence, suggesting a specific regulatory mechanism for generating CYP51 mRNA in testis different from that in liver and ovary.
Noshiro
M
M
Department of Biochemistry, Hiroshima University School of Dentistry.
Aoyama
Y
Y
Kawamoto
T
T
Gotoh
O
O
Horiuchi
T
T
Yoshida
Y
Y
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002874:Chromosome Mapping; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D019143:Evolution, Molecular; D005260:Female; D016678:Genome; D008099:Liver / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D010053:Ovary / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics*; D011544:Pseudogenes; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D058886:Sterol 14-Demethylase; D013737:Testis / Q000378:metabolism
C548417:Cyp51 protein, rat; D012333:RNA, Messenger; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; D058886:Sterol 14-Demethylase