| Six1 is an evolutionary conserved transcription factor which belongs to the sine oculis homeobox protein family (SIX). It plays an essential role in vertebrate's skeletal muscle formation and development. The skeletal muscle development during embryonic stages depends on a complex regulatory network, however, with highly precise regulation process. Sixl is an important member of the genes controlling muscle development, associates with the determination and differentiation of myogenic cell, and plays a crucial role not only in the formation of muscle fiber and muscle cell proliferation but also in determination of muscle fiber types. Previous studies concentrated on the roles of Sixl in mammalian myogenic cells' determination, while limited knowledge involved in embryonic and postanatal stages. The relative expression levels of Six1 gene in duck different tissues were detected in this research, and also the developmental expression in skeletal muscle was studied. Furthermore, we constructed the duck six1 transfection vectors and transfect them into duck myoblast in vitro to investigate its regulation function on MyoD and Myf5. The results showed that:1. We cloned duck Six1 gene about (1154bp) for the first time, and the coding domain sequence (CDS) contains 849bp, encoding 282 amino acids. Homology analysis showed that Six1 sequence is highly conserved among species.2. Bioinformatic analysis showed that duck Six1 peptide has conserved domain, which is called Homeodomain. At the N-terminal region of Homeodomain, there is another conserved domain called Sixdomain, which may be essential for protein-protein interaction.3. Tissue distribution expression of Six1 showed different significantly in 30 days ducks. The highest expression was found in breast muscle, followed by leg muscle, then followed by pancreas, lung and spleen. Tissue distribution expression of Sixl was not influenced by gender.4. The developmental expression patterns of Six1 gene within breast and leg muscle during embryonic development stages were similar. The expression level of Sixl increased with age growth, and sharply decreased on 2 days after hatching, then increased thereafter in breast muscle. Six1 expression increased from 2 to 8 weeks in leg muscle. The expression of Six1 in 11 month was higher than 8 weeks in leg muscle.5. We constructed the duck Six1 transfection vector (pEGFPN1-Six1), and transfected them into duck myoblasts in vitro. In normal fluorescence logging, transcription level of Six1, Myf5 and MyoD were significantly (P<0.01) increased, indicating the role of Six1 on regulating the expression of Myf5 and MyoD which involved in duck myoblast. |
