5'-flanking sequences of zebrafish fast myosin heavy chain genes regulate unique expression in the anterior, medial subsection and posterior tail somites of the skeletal muscle.
In zebrafish, fast muscle-specific myosin heavy chain genes have their unique expression patterns in a well-defined and restricted region of the skeletal muscle. However, the transcriptional regulatory mechanisms involved have remained unclear. Here, we examined the regulation of spatio-temporal expression patterns of myhz1 (myhz1.1, myhz1.2 and myhz1.3) and myhz2 during their development by using transient gene and stable transgenic techniques. Embryos microinjected with different length 5'-flanking sequences of myhz1 conjugated with the enhanced green fluorescent protein (EGFP) gene showed EGFP expression in the anterior and medial subsections of somites, but not in the tail somite region. In contrast, embryos microinjected with different length 5'-flanking sequences of myhz2 showed EGFP expression exclusively at the posterior tail somite domain. Promoter deletion analyses demonstrated that reduced EGFP fluorescence typically is correlated with smaller 5'-flanking sequences. The immunohistochemical observation revealed that zebrafish larvae provided with the transient gene and those from stable transgenic lines consistently expressed EGFP in the fast muscle fibers. r-VISTA plot identified one common conserved region of about 140°bp among myhz1.1, myhz1.2 and myhz1.3. Deletion of this conserved region from the 5'-flanking sequence of each myhz1 markedly reduced EGFP expression in its unique spatial somite region. Deletion mutation analysis demonstrated that myhz2 expression in the tail somite region might be mediated by Tbx (family of transcription factors having a common DNA-binding sequence known as T-box) binding elements. In summary, 5'-flanking sequences of myhz1 and myhz2 regulate their unique expression patterns in a well-defined and restricted somite region of the skeletal muscle in zebrafish.
School of Fisheries and Aquaculture Sciences, Universiti Malaysia Terengganu, 21030 Kuala-Terengganu, Terengganu, Malaysia; Institute of Tropical Aquaculture, Universiti Malaysia Terengganu, 21030 Kuala-Terengganu, Terengganu, Malaysia; Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.
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Asaduzzaman
Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.
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Shakur Ahammad
Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.
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Asakawa
Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.
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Kinoshita
Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan; School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan. Electronic address: swatabe@kitasato-u.ac.jp.
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Watabe
D024506:5' Flanking Region / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D017124:Conserved Sequence; D018507:Gene Expression Regulation, Developmental; D007814:Larva / Q000235:genetics; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000196:embryology*; D018995:Myosin Heavy Chains / Q000235:genetics*; D009928:Organ Specificity; D011401:Promoter Regions, Genetic / Q000235:genetics; D019170:Somites / Q000378:metabolism*; D014158:Transcription, Genetic; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics*; D029961:Zebrafish Proteins / Q000235:genetics
D029961:Zebrafish Proteins; D018995:Myosin Heavy Chains
5′-flanking region; Myosin heavy chain; Promoter analysis; Transcriptional regulation; Zebrafish