title: The human hyaluronan synthase 2 gene is a primary retinoic acid and epidermal growth factor responding gene.
abstract: Hyaluronan is an abundant and rapidly turned over matrix molecule between the vital cell layers of the epidermis and subject to large concentration changes associated with keratinocyte proliferation, migration, and differentiation induced by paracrine and endocrine factors like epidermal growth factor (EGF) and all-trans-retinoic acid (RA). We found that in REK cells EGF and all-trans-RA up-regulated hyaluronan synthase 2 (Has2) gene expression within 2 h 4-fold each and in HaCaT human immortal keratinocytes 8- and 33-fold, respectively. The first 10 kb of the human Has2 promoter were scanned in silico and in vitro for potential response elements of signal transducer and activator of transcription (STAT) or RA receptor (RAR) proteins. We identified a STAT-response element in the proximal promoter region and confirmed its functionality in response to EGF by chromatin immunoprecipitation (ChIP) assays. Direct in vitro binding of RARs to four RARE candidates within the Has2 promoter could not be observed at stringent gel shift conditions, but reporter gene assays demonstrated functionality of a complex of two of these RAREs located approximately 1200 bp upstream of the transcription start site. Moreover, ChIP assays using antibodies against nine nuclear proteins monitored all-trans-RA-dependent binding of RAR, retinoid X receptor, mediator protein, and RNA polymerase II and also histone 4 acetylation to a promoter region containing the complex RARE. Taken together, the human Has2 gene is a potent primary EGF and all-trans-RA responding gene with a complex regulation.
authors.affiliation: Department of Biochemistry, University of Kuopio, FIN-70211 Kuopio, Finland.
authors.forename: Katri
authors.initials: K
authors.lastname: Saavalainen
authors.forename: Sanna
authors.initials: S
authors.lastname: Pasonen-Seppänen
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Dunlop
authors.forename: Raija
authors.initials: R
authors.lastname: Tammi
authors.forename: Markku I
authors.initials: MI
authors.lastname: Tammi
authors.forename: Carsten
authors.initials: C
authors.lastname: Carlberg
mesh_terms: D000107:Acetylation; D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation; D002460:Cell Line; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D002843:Chromatin / Q000737:chemistry; D047369:Chromatin Immunoprecipitation; D004268:DNA-Binding Proteins / Q000378:metabolism; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D004815:Epidermal Growth Factor / Q000378:metabolism*; D004817:Epidermis / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000378:metabolism / Q000502:physiology*; D006657:Histones / Q000737:chemistry; D006801:Humans; D000076002:Hyaluronan Synthases; D006820:Hyaluronic Acid / Q000737:chemistry; D015603:Keratinocytes / Q000378:metabolism; D008024:Ligands; D008156:Luciferases / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012319:RNA Polymerase II / Q000737:chemistry; D051381:Rats; D018168:Receptors, Retinoic Acid / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050794:STAT1 Transcription Factor; D012867:Skin / Q000378:metabolism; D013816:Thermodynamics; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism; D014162:Transfection; D014212:Tretinoin / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D002843:Chromatin; D004268:DNA-Binding Proteins; D006657:Histones; D008024:Ligands; D018168:Receptors, Retinoic Acid; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D015534:Trans-Activators; D014212:Tretinoin; D004815:Epidermal Growth Factor; D006820:Hyaluronic Acid; D008156:Luciferases; D014453:Glucuronosyltransferase; C101754:HAS2 protein, human; D000076002:Hyaluronan Synthases; D012319:RNA Polymerase II