title: Genomic structure, alternative maturation and tissue expression of the human BBOX1 gene.
abstract: Gamma-butyrobetaine hydroxylase (BBOX1) is the enzyme responsible for the biosynthesis of l-carnitine, a key molecule of fatty acid metabolism. This cytosolic dimeric protein belongs to the dioxygenase family. In human, enzyme activity has been detected in kidney, liver and brain. The human gene encoding gamma-butyrobetaine hydroxylase is located on chromosome 11. Although the protein structure and activity have been extensively described, little information is available concerning BBOX1 structure and expression. In this study, the organization of the human gene was determined. The structure and functions of the 5'- and 3'-untranslated regions of the human BBOX1 mRNA were characterized in kidney, liver and brain. Our experiments revealed that the transcription initiation of the human BBOX1 gene might occur at 3 different exons, and that the expression level of each type of transcript is organ-specific. We showed that the use of 3 different promoters is responsible for the 5'-end heterogeneity. Investigations on BBOX1 mRNA maturation highlighted an alternative polyadenylation mechanism that generates two 3'-untranslated regions differing by their length. This alternative polyadenylation exhibited a tissue specificity.
authors.affiliation: Inserm - CRI-Dijon, University of Dijon, UFR Sciences Vie, 6 Blvd. Gabriel, 21000 Dijon, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Rigault
authors.forename: Françoise
authors.initials: F
authors.lastname: Le Borgne
authors.forename: Jean
authors.initials: J
authors.lastname: Demarquoy
mesh_terms: D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D017398:Alternative Splicing; D001483:Base Sequence; D001921:Brain / Q000201:enzymology; D018076:DNA, Complementary / Q000235:genetics; D005091:Exons; D020224:Expressed Sequence Tags; D015870:Gene Expression; D006801:Humans; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014018:Tissue Distribution; D014158:Transcription, Genetic; D050563:gamma-Butyrobetaine Dioxygenase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D018076:DNA, Complementary; D012333:RNA, Messenger; D050563:gamma-Butyrobetaine Dioxygenase