title: Recruitment of serum response factor and hyperacetylation of histones at smooth muscle-specific regulatory regions during differentiation of a novel P19-derived in vitro smooth muscle differentiation system.
abstract: Little is known regarding transcriptional regulatory mechanisms that control the sequential and coordinate expression of genes during smooth muscle cell (SMC) differentiation. To facilitate mechanistic studies of SMC differentiation, we established a novel P19-derived clonal cell line (designated A404) harboring a smooth muscle (SM) alpha-actin promoter/intron-driven puromycin resistance gene. Retinoic acid plus puromycin treatment stimulated rapid differentiation of multipotential A404 cells into SMCs that expressed multiple SMC differentiation marker genes, including the definitive SM-lineage marker SM myosin heavy chain. Using this system, we demonstrated that various transcription factors were upregulated coincidentally with the expression of SMC differentiation marker genes. Of interest, the expression of serum response factor (SRF), whose function is critical for SMC-specific transcription, was high in undifferentiated A404 cells, and it did not increase over the course of differentiation. However, chromatin immunoprecipitation analyses showed that SRF did not bind the target sites of endogenous SMC marker genes in chromatin in undifferentiated cells, but it did in differentiated A404 cells, and it was associated with hyperacetylation of histones H3 and H4. The present studies define a novel cell system for studies of transcriptional regulation during the early stages of SMC differentiation, and using this system, we obtained evidence for the involvement of chromatin remodeling and selective recruitment of SRF to CArG elements in the induction of cell-selective marker genes during SMC differentiation.
authors.affiliation: Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA.
authors.forename: I
authors.initials: I
authors.lastname: Manabe
authors.forename: G K
authors.initials: GK
authors.lastname: Owens
mesh_terms: D000107:Acetylation / Q000187:drug effects; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000943:Antigens, Differentiation / Q000096:biosynthesis; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line; D002843:Chromatin / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006657:Histones / Q000378:metabolism*; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000096:biosynthesis; D014411:Neoplastic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism*; D011233:Precipitin Tests; D011691:Puromycin / Q000494:pharmacology; D012045:Regulatory Sequences, Nucleic Acid / Q000187:drug effects / Q000502:physiology*; D026362:Serum Response Factor; D014157:Transcription Factors / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D000943:Antigens, Differentiation; D002843:Chromatin; D004268:DNA-Binding Proteins; D006657:Histones; D009687:Nuclear Proteins; D026362:Serum Response Factor; D014157:Transcription Factors; D011691:Puromycin; D014212:Tretinoin; D018995:Myosin Heavy Chains