title: The unique 5-flanking region of the human basic calponin gene.
abstract: Calponin has been implicated in the regulation of smooth muscle contraction. Basic calponin, one of the calponin isoforms, is expressed exclusively in smooth muscle cell (SMC)-rich tissues, and is considered to be a phenotypic marker of differentiated SMC. To define the molecular mechanism of SMC-specific gene transcription in humans, we isolated and characterized the 5'-flanking region of this gene. Sequence analysis revealed that several putative cis-acting elements were clustered within a 500-bp sequence upstream of the transcription start site. However, the 1.9-kb promoter region obtained herein lacked a completely matched consensus sequence of the CArG box that is commonly identified in the promoter region of other SMC-specific genes. A luciferase assay demonstrated that the 1.9-kb promoter region was sufficient to drive a basal transcriptional activity not only in human vascular smooth muscle cells (VSMC) but also in HeLa cells. In particular, the sequence between positions -1,906 and -867 had a significantly higher transcriptional activity in VSMC than in HeLa cells. In contrast, the promoter activity was drastically decreased between positions -327 and -257 in both types of cells. These results indicate that the sequence spanning from position -327 to -257 contains an essential domain involved in the basal transcriptional activity of the human basic calponin gene, and that the distal region of the 1.9-kb 5'-flanking sequence presented herein may play a pivotal role in the phenotypic modulation of VSMC.
authors.affiliation: Second Department of Internal Medicine, Ehime University School of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kitami
authors.forename: M
authors.initials: M
authors.lastname: Maguchi
authors.forename: W
authors.initials: W
authors.lastname: Nishida
authors.forename: T
authors.initials: T
authors.lastname: Okura
authors.forename: K
authors.initials: K
authors.lastname: Kohara
authors.forename: K
authors.initials: K
authors.lastname: Hiwada
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D001483:Base Sequence; D002135:Calcium-Binding Proteins / Q000235:genetics*; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D008840:Microfilament Proteins; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000235:genetics*; D009124:Muscle Proteins / Q000235:genetics; D009131:Muscle, Smooth, Vascular / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic; D000096985:Calponins
chemical_list: D020121:5' Untranslated Regions; D002135:Calcium-Binding Proteins; D008840:Microfilament Proteins; D009124:Muscle Proteins; D020033:Protein Isoforms; D000096985:Calponins