title: Transcription start sites and epigenetic analysis of the HSD17B10 proximal promoter.
abstract: BACKGROUND
  Hydroxysteroid (17beta) dehydrogenase X (HSD10) is a multifunctional protein encoded by the HSD17B10 gene at Xp11.2. In response to stress or hypoxia-ischemia its levels increase rapidly. Expression of this gene is also elevated significantly in colonic mucosa of the inactive ulcerative colitis patients. However, accurate information about its several transcripts is still lacking, and additional evidence for its escape from X-chromosome inactivation remains to be obtained in order to help settle a debate (He XY, Dobkin C, Yang SY: Does the HSD17B10 gene escape from X-inactivation? Eur J Hum Genet 2011, 19: 123-124).
  
  
  RESULTS
  Two major HSD17B10 transcription start sites were identified by primer extension at -37 and -6 as well as a minor start site at -12 nucleotides from the initiation codon ATG. Epigenetic analysis of the 5'-flanking region of the HSD17B10 gene showed that there was little 5-methylcytosine (< 3%) in a normal male, and that none of CpG dinucleotides in the CpG island approached 50% methylation in females.
  
  
  CONCLUSIONS
  The actual length of first exon of the HSD17B10 gene was found to be about a quarter larger than that originally reported. Its transcripts result from a slippery transcription complex. The hypomethylation of the CpG island provides additional evidence for the variable escape of the HSD17B10 gene from X-chromosome inactivation which could influence the range of severity of HSD10 deficiency, an inherited error in isoleucine metabolism, in heterozygous females.
authors.affiliation: Department of Developmental Biochemistry, NYS Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA. songyu.yang@csi.cuny.edu
authors.forename: Song-Yu
authors.initials: SY
authors.lastname: Yang
authors.forename: Carl
authors.initials: C
authors.lastname: Dobkin
authors.forename: Xue-Ying
authors.initials: XY
authors.lastname: He
authors.forename: W Ted
authors.initials: WT
authors.lastname: Brown
mesh_terms: D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D044503:5-Methylcytosine / Q000737:chemistry / Q000378:metabolism; D001483:Base Sequence; D041321:Chromosomes, Human, X; D018899:CpG Islands; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D005091:Exons; D005260:Female; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D024363:Transcription Initiation Site
chemical_list: D044503:5-Methylcytosine; D015094:3-Hydroxyacyl CoA Dehydrogenases; C108634:HSD17B10 protein, human