No abstract

The gene encoding aromatase P-450 (CUP XIX) has been isolated from two types of human genomic DNA libraries. It spans at least 70 kb and consists of 10 exons. The translational initiation site and the termination site are located in exon 2 and exon 10, respectively. The promoter region of the gene contains a TATA box, a CAAT box and two putative AP-1 binding sites beginning at -28, -83, -55 and -68 bp, respectively, from the transcriptional initiation site. In addition, a palindromic nucleotide sequence is observed between -209 and -196 and two types of repetitious hexanucleotide (consensus : AATGAA and CCATh$) are also present within the regions between -485 and -433 and between -358 and -331. Transient expression studies of chloramphenicol acetyltransferase constructs bearing various lengths of 5'-flanking region of the gene show that the region between -500 and -243 contains negative cis-acting element(s), whereas the region between -242 and -183 is required for efficient transcriptional activity. Northern blot analysis demonstrates that the expression of aromatose P-450 gene is remarkably stimulated by treatment of cells with 12-0-tetradecanoyl-phorbol 13-acetate. By chloramphenicol acetyltransferase assay the region up to nucleotide position -242 relative to the transcriptional initiation site is shown to participate in the transcriptional responsiveness to this phorbol ester.Human aromatase P-450 is the product of CYP XIX gene More recently several groups, including ours, reported the isolation and nucleotide sequence of cDNA clones encoding aromatase P-450 by screening cDNA libraries with synthetic oligonucleotides designed on the basis of the amino acid sequence of the enzyme [19,20] or antibodies against the purified enzyme [21,22]. Our previous studies also demonstrated that Correspondence to Y. Shizuta,

No abstract

The promoter region of the poly(ADP-ribose) polymerase gene has been isolated using a Sau3AI genomic library derived from human leukocyte. It lacks typical transcriptional regulatory elements such as TATA and CAAT boxes, but it contains two potential Spl binding sites and three putative AP-2 binding elements. The region up to nucleotide position -99 in relation to the predominant transcriptional initiation site exhibits promoter activity as judged by chloramphenicol acetyltransferase assay and the activity is enhanced both by CAMP and by phorbol ester. Northern blot and Western blot analyses have revealed that expression of the polymerase gene is also stimulated by both of these compounds in cultured HeLa cells. Southern blot hybridization of genomic DNA separately digested with various endonucleases gives a discrete single band in each case when the 5'-untranslated region of the polymerase cDNA is used as a probe. These results indicate that poly(ADP-ribose) polymerase is encoded by a unique gene whose expression is regulable by CAMP and by phorbol ester.Poly(ADP-ribose) polymerase, an enzyme localized in the nuclei of eukaryotic cells, catalyzes the polymerization of the ADP-ribose moiety of NAD to form poly(ADP-ribose) which is covalently bound to various nuclear proteins [l, 21. Recently, it has been demonstrated that the enzyme consists of three proteolytically separable domains, the first for binding of DNA, the second for automodification and the third for binding of the substrate, NAD [3 -71.The physiological function of this enzyme is not as yet fully understood, but several lines of evidence suggest that it may be involved in many biologically important processes such as DNA repair, DNA replication, RNA synthesis and cell differentiation (for review see [2]). Nevertheless, how poly(ADP-ribosy1)ation participates in these important biological mechanisms and how the gene expression of this enzyme is regulated in eukaryotic cells remain to be elucidated.In our preceding papers, we reported the isolation of cDNA clones for human poly(ADP-ribose) polymerase and determined the complete nucleotide sequence of the cDNA [8 -101. In order to investigate further the molecular genetic characteristics of the enzyme in living cells, we attempted to Correspondence to Y. Shizutd,

No abstract