Regulation of gene expression mediating indeterminate muscle growth in teleosts. (August 2015)

• Record Type: Journal Article
• Authors: Ahammad, A.K. Shakur; Asaduzzaman, Md; Asakawa, Shuichi; Watabe, Shugo; Kinoshita, Shigeharu
• Is Part Of: Mechanisms of development. Volume 137(2015)
• Page Start: 53
• Page End: 65
• Publication Date: 2015-08
• Subjects: Indeterminate muscle growth -- Muscle hyperplasia -- Teleost -- Myosin heavy chain -- Promoter analysis; ANOVA analysis of variance -- DAPI diamidine-20-phenylindole dihydrochloride -- EGFP enhanced green fluorescent protein -- MEF2 myocyte enhancer element 2 -- MYH myosin heavy chain -- NFAT nuclear factor of activated T-cell -- Pax3 paired box 3 -- PFA paraformaldehyde -- RACE rapid amplification of cDNA ends -- SPSS statistical package for social science -- TBSTw Tris-buffered saline with 0.1% tween 20 -- TEEA transient embryonic excision assay; Developmental biology -- Periodicals; Molecular biology -- Periodicals; Developmental Biology -- Periodicals; Molecular Biology -- Periodicals; Biologie du développement -- Périodiques; Biologie moléculaire -- Périodiques; Developmental biology; Molecular biology; Periodicals; Electronic journals; 571.8
• DOI: 10.1016/j.mod.2015.02.006
• Languages: English
• ISSNs: 0925-4773

Abstract

Highlights: First report of the promoter involved in teleost indeterminate muscle growth. Molecular cascade conserved between large (torafugu) and small (zebrafish) fish. Duration of promoter activation differs between large and small fish. Several transcription factors including NFAT may be involved in promoter activity. Abstract: Teleosts are unique among vertebrates due to their indeterminate muscle growth, i.e., continued production of neonatal muscle fibers until death. However, the molecular mechanism(s) underlying this property is unknown. Here, we focused on the torafugu ( Takifugu rubripes ) myosin heavy chain gene, MYHM2528-1, which is specifically expressed in neonatal muscle fibers produced by indeterminate muscle growth. We examined the flanking region of MYHM2528-1 through an in vivo reporter assay using zebrafish ( Danio rerio ) and identified a 2100 bp 5′-flanking sequence that contained sufficient promoter activity to allow specific gene expression. The effects of enhanced promoter activity were observed at the outer region of the fast muscle and the dorsal edge of slow muscle in zebrafish larvae. At the juvenile stage, the promoter was specifically activated in small diameter muscle fibers scattered throughout fast muscle and in slow muscle near the septum separating slow and fast muscles. This spatio-temporal promoter activity overlapped with known myogenic zones involved in teleost indeterminate muscle growth. A deletion mutant analysis revealed that the −2100 to −600 bp 5′flanking sequence of MYHM2528-1 is essential for promoter activity. This region contains putative binding sites for several representative myogenesis-related transcription factors and nuclear factor of activated T-cell (NFAT), a transcription activator involved in regeneration of mammalian adult skeletal muscle. A significant reduction in the promoter activity of the MYHM2528-1 deletion constructs was observed in accordance with a reduction in the number of these binding sites, suggesting the involvement of specific transcription factors in indeterminate muscle growth.