Molecular cloning and characterization of the Myf5 gene in sea perch (Lateolabrax japonicus).

The cDNA of myogenic factor (Myf5) was isolated from sea perch (Lateolabrax japonicus) using Reverse-transcription Polymerase Chain Reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The 5' flanking sequence of the cDNA contains a TATA box, GC box, CAAT box, several E box sites and muscle-specific regulatory elements determined by genome walking. The Myf5 gene consists of 3 exons and 2 introns. The open reading frame was found to code a protein with 238 amino-acid residues, containing the conserved basic helix-loop-helix domain (bHLH). RT-PCR indicated the Myf5 was highly expressed in muscle, and weakly expressed in brain, eyes, spleen, gill, liver, kidney, intestine and heart. In early embryonic stages, Myf5 mRNA transcripts are highly detectable in the early gastrula stage while decreasing up to a low level at the late gastrula stage, subsequently greatly increased up to the highest level in the somites stage, then gradually decreases from the tail-bud stage to 15 d larvae after hatching, but they are still detectable. Further, Myf5 mRNA was expressed in several sea perch cell lines such as LJES1, LJHK, LJH-1, LJH-2, LJS, LJL, although its expression level varied greatly among different cell lines.