Stimulatory and inhibitory mechanisms of slow muscle-specific myosin heavy chain gene expression in fish: Transient and transgenic analysis of torafugu MYHM86-2 promoter in zebrafish embryos

► MYHM86-2 is highly expressed in slow muscle fibers of torafugu embryos and larvae. ► MYHM86-2 promoter activity depends on the hedgehog signaling. ► Sox6 binding elements inhibits MYHM86-2 expression in fast muscle fibers. ► Sox6 elements function as transcriptional repressor of MYHM86-2 promoter activity. ► NFAT and MEF2 binding elements play a key role for directing MYHM86-2 expression.