Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Estrone sulfate is the predominant form of estrogens found in the circulation in women and could thus serve as precursor for active estrogens in target tissues by removal of the sulfate group through the action of endogenous steroid sulfatase. Recently, we isolated a cDNA encoding human placental estrogen sulfotransferase that differs from brain aryl sulfotransferase only in the 5'-noncoding sequence. To increase our knowledge of the regulation and tissue-specific expression of sulfotransferase gene, we screened a lambda EMBL3 library of human leucocyte genomic DNA using the estrogen sulfotransferase cDNA as probe and isolated a clone containing almost the whole gene sequence. Sequencing of the gene indicates that it is included in approximately 7.7 kilobases and contains nine short exons separated by eight introns. The two first exons, named exon 1a and exon 1b, are noncoding and correspond to the 5'-untranslated sequences of human brain and human placental estrogen sulfotransferase cDNAs, respectively. Transfection of chloramphenicol acetyltransferase reporter gene vectors containing the 5'-flanking sequence upstream from exon 1a and exon 1b in human adrenal adenocarcinoma cells indicates that both sequences possess promoter activity. The present results thus indicate that brain aryl sulfotransferase and placental human placental estrogen sulfotransferase mRNA species are transcribed from a single gene by alternate exon 1a and exon 1b promoters, respectively. Using DNA from panels of human/rodent somatic cell hybrids and amplification of the gene by polymerase chain reaction, the human placental estrogen sulfotransferase gene was assigned to chromosome 16.
 ...
PMID:Structure of human estrogen and aryl sulfotransferase gene. Two mRNA species issued from a single gene. 796 57

Human dehydroepiandrosterone sulfotransferase (DHEA-ST) catalyzes the sulfonation of DHEA, cholesterol, pregnenolone as well as androsterone. RNA blot analysis shows two DHEA-ST mRNA species of 1.3 and 1.8 kb that are expressed similarly in liver and adrenals. To determine whether the form expressed in adrenals is distinct or identical with the one expressed in liver, we have cloned and sequenced the 1.8 kb DHEA-ST cDNA from human adrenal cDNA library. Except for one nucleotide difference, the human adrenal and liver DHEA-ST cDNAs are identical. Using expression vectors containing the chloramphenicol acetyltransferase (CAT) reporter gene ligated to various fragments of the DHEA-ST gene promoter, we have shown that DHEA-ST gene promoter activity is stimulated by estradiol (E2). The E2 stimulation is inhibited by the anti-estrogen EM-139. In contrast to human DHEA-ST, guinea pig hydroxysteroid sulfotransferases show high substrate- and stereo-selectivity. We have cloned a chiral-specific pregnenolone sulfotransferase (PREG-ST) which catalyzes mainly the transformation of pregnenolone to pregnenolone sulfate. Estrogen sulfotransferase catalyzes the conversion of estrone and estradiol to their inactive sulfated forms and could thus play a major role in the control of estrogen levels in target tissues. Recently, using a probe derived from bovine estrogen sulfotransferase, we have cloned a cDNA and gene that we first named human estrogen sulfotransferase (hEST) since the expressed enzyme is able to transform estrone to estrone sulfate. Actually, the Hugo nomenclature committee named this gene STM gene because it also codes for monoamine-sulfating phenol-sulfotransferase (M-PST). hEST1 possesses the same coding and 3'-untranslated region as human brain aryl sulfotransferase (HAST) and M-PST, but different 5'-noncoding region. Analysis of hEST1 gene sequence indicates that hEST1 and HAST3 or M-PST mRNA species are transcribed from a single hEST1 gene by alternative promoters using two separate exon 1, named exon Ia and exon Ib. We also described the identification of a third mRNA species (M-PST gamma) issued from the STM gene and the characterization of the structure of the phenol-sulfating phenolsulfotransferase (STP) gene that is highly homologous to the STM gene. Similar to STM, the STP gene generates multiple mRNA species that differ only in the 5'-untranslated sequence.
 ...
PMID:Steroid sulfotransferases. 894 92