title: First identification and functional analysis of the human xylosyltransferase II promoter.
abstract: Recently, we demonstrated that the human xylosyltransferase II (XT-II) has enzymatic activity and is able to catalyze the initial and rate-limiting step in the biosynthesis of glycosaminoglycans (GAGs) like chondroitin and dermatan sulfate, as well as heparan sulfate and heparin. Therefore, this enzyme also very likely assumes a crucial regulatory role in the biosynthesis of proteoglycans (PGs). In this study, we identified and characterized for the first time the XYLT2 gene promoter region and transcription factors involved in its regulation. Several binding sites for members of the Sp1 family of transcription factors were identified as being necessary for transcriptional regulation of the XYLT2 gene. This was determined by mithramycin A treatment, electrophoretic mobility shift and supershift assays, as well as numerous site-directed mutagenesis experiments. Different 5' and 3' deletion constructs of the predicted GC rich promoter region, which lacks a canonical TATA and CAAT box, revealed that a 177 nts proximal promoter element is sufficient and indispensable to drive the constitutive transcription in full strength in HepG2 hepatoma cells. In addition, we also detected the transcriptional start site using 5'-RACE (rapid amplification of cDNA ends). Our results provide an insight into transcriptional regulation of the XYLT2 gene and may contribute to understanding the manifold GAG-involving processes in health and disease.
authors.affiliation: Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum NRW, Universitätsklinik der Ruhr-Universität Bochum, Bad Oeynhausen, Germany. mueller.benjamin@mh-hannover.de
authors.forename: Benjamin
authors.initials: B
authors.lastname: Müller
authors.forename: Christian
authors.initials: C
authors.lastname: Prante
authors.forename: Cornelius
authors.initials: C
authors.lastname: Knabbe
authors.forename: Knut
authors.initials: K
authors.lastname: Kleesiek
authors.forename: Christian
authors.initials: C
authors.lastname: Götting
mesh_terms: D024509:3' Flanking Region; D024506:5' Flanking Region; D001483:Base Sequence; D020862:GC Rich Sequence; D015972:Gene Expression Regulation, Neoplastic; D056945:Hep G2 Cells; D006801:Humans; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010430:Pentosyltransferases / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D016329:Sp1 Transcription Factor / Q000378:metabolism; D014158:Transcription, Genetic; D000097608:UDP Xylose-Protein Xylosyltransferase
chemical_list: D010430:Pentosyltransferases; D016329:Sp1 Transcription Factor; D000097608:UDP Xylose-Protein Xylosyltransferase