title: Stimulatory and inhibitory mechanisms of slow muscle-specific myosin heavy chain gene expression in fish: transient and transgenic analysis of torafugu MYH(M86-2) promoter in zebrafish embryos.
abstract: The myosin heavy chain gene, MYHM86-2, exhibited restricted expression in slow muscle fibers of torafugu embryos and larvae, suggesting its functional roles for embryonic and larval muscle development. However, the transcriptional mechanisms involved in its expression are still ambiguous. The present study is the first extensive analysis of slow muscle-specific MYHM86-2 promoter in fish for identifying the cis-elements that are crucial for its expression. Combining both transient transfection and transgenic approaches, we demonstrated that the 2614bp 5'-flanking sequences of MYHM86-2 contain a sufficient promoter activity to drive gene expression specific to superficial slow muscle fibers. By cyclopamine treatment, we also demonstrated that the differentiation of such superficial slow muscle fibers depends on hedgehog signaling activity. The deletion analyses defined an upstream fragment necessary for repressing ectopic MYHM86-2 expression in the fast muscle fibers. The transcriptional mechanism that prevents MYHM86-2 expression in the fast muscle fibers is mediated through Sox6 binding elements. We also demonstrated that Sox6 may function as a transcriptional repressor of MYHM86-2 expression. We further discovered that nuclear factor of activated T cells (NFAT) binding elements plays a key role and myocyte enhancer factor-2 (MEF2) binding elements participate in the transcriptional regulation of MYHM86-2 expression.
authors.affiliation: Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.
authors.forename: Md
authors.initials: M
authors.lastname: Asaduzzaman
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Kinoshita
authors.forename: Sharmin Siddique
authors.initials: SS
authors.lastname: Bhuiyan
authors.forename: Shuichi
authors.initials: S
authors.lastname: Asakawa
authors.forename: Shugo
authors.initials: S
authors.lastname: Watabe
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000187:drug effects / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008297:Male; D008845:Microinjections; D018657:Muscle Fibers, Slow-Twitch / Q000166:cytology* / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D018006:Myogenic Regulatory Factors / Q000235:genetics / Q000378:metabolism; D018995:Myosin Heavy Chains / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D023741:Takifugu / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection; D019076:Transgenes; D014704:Veratrum Alkaloids / Q000494:pharmacology; D015027:Zebrafish / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C522156:Mef2 protein, zebrafish; D018006:Myogenic Regulatory Factors; C531459:Sox6 protein, zebrafish; D014704:Veratrum Alkaloids; D029961:Zebrafish Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D018995:Myosin Heavy Chains; C000541:cyclopamine