Abstract：The transcription factor myf6 is a member of the MyoD family that plays a key role in myogenic lineage determination. This study was carried out to clone and analyze sequence of goose (Anser anser) myf6 gene, and to reveal its expression during embryonic stage and after overfeeding. In order to obtain full-length of myf6 cDNA, RT-PCR and rapid-amplification cDNA ends (RACE) were used. The structure and function of myf6 gene was analyzed by bioinformatics methods. Real-time fluorescence quantitative RT-PCR was performed to detect myf6 mRNA expression levels in various embryonic stages and after overfeeding status. A full-length of 1 196 bp myf6 cDNA contains an open reading frame, the 90 bp 5'UTR and the 383 bp 3'UTR (GenBank Accession: JQ905627). The open reading frame was 723 bp, which encodes polypeptides of 240 amino acids, with a calculated relative molecular mass of 26.214 4 kD and pI of 5.68. The myf6 was a kind of hydrophilic and unstable protein, with average of hydropathicity -0.595. The myf6 protein was predicted to distinctly had Basic and HLH protein domains, and the bHLH domain of goose myf6 was forming α-helix dimer that was like a scissors, and HLH sequence was highly homologous among different species. Multiple sequence comparisons showed Anser anser myf6 had high homology with Anas platyrhynchoss at 98.62%, about 81% with mammals, and the lowest with fish at only 62%~66%. Phylogenetic relationship analysis indicated that all mammals, birds, bony fish each was formed a large branch, and amphibians was formed an independent branch. Anser anser was firstly clustered with Anas platyrhynchoss and also closely related with Gallus gallus, which was similar to the results of the biological classification. Real-time PCR was performed to analyze the expression profiling of myf6, results showed that goose myf6 was expressed in early embryos at E7, then the expression level gradually increased, the expression level of myf6 in muscle reached the peak at E18, then decreased and stabilized before hatch. The expression level of myf6 at E21 was nearly four times as E25, and after E25 the expression of myf6 was gradually stabilized. And the expression level at E18 was significantly different from those at E14, E15, E25 and E28 (P＜0.01). The similar results were also seen between E21 and E25, E28 (P＜0.01), and E14, E15 (P＜0.05). In addition to these, the expression of myf6 in the breast muscle and thigh muscle of overfeeding group was much higher than that in the control group (P＜0.05). The results showed the expression of myf6 is tissues-specific, and also provide theoretical foundation for the further study of the structure and function of myf6 in goose myogenesis and development during embryonic stage.
