Regulation Gene Of The Skeletal Muscle Growth In Animals And The Adipose Aggradation In Pigs

The MyoD gene family can control the myoblast proliferation and differentiation, which consisting of MyoDl, myogenin, myf-5 and myf-6. The PCR-SSCP and Sequencing analysis were conducted on the partial nucleotide sequence of Myf5 gene in Qinchuan Cattle, Tianzhu White Yak, Sichuan Maiwa Yak. The results showed that two polymorphic sites were found in the exon 1. In the Qinchuan Cattle, one of the large beef cattle in China , the body weight and heart girth were higher in CC genotype than those in DD at 6 month and 12 month age ,these indicated that Myf5 gene variation contributes to body growth in cattle.Myostatin (MSTN), also known as GDF-8, as a member of the transforming growth factor-beta superfamily, has been shown to be a negative regulation of myogenesis that is expressed in vertebrate skeletal muscles. MSTN null mice show a doubling of muscle mass compared with normal mice. There was a polymorphic site in the exon 1 of MSTN in Piedmontese Cattle, Qinchuan Cattle, Tianzhu White Yak, but the gene frequency was very low in Qinchuan Cattle, Tianzhu White Yak. To verify the relationship between the genotypes of MSTN and the phenotypes, we should enlarge the sample size for further analysis.Uncoupling proteins (UCPs) are mitochondrial membrane transporters involved in themogenesis. Metabolized energy is converted into heat by uncoupling of the oxidation and phosphorylation on respiration chain from ATP synthesis. UCPs affect body weight gain (obesity), resting metabolic rates and feed intake, which are all involved in energy balance. PCR-SSCP, PCR- RFLP, sequencing analysis ,were conducted on the partial nucleotide sequence of pig UCP2 and UCP3 gene in the lean meat type , Landrace, Large White Pig, and the obesity type, Meishan , Wuzhishan, Gansu Black Pig, only there was a mutation in exon 4 in UCP2 gene, these results indicated the relatively high conservation of UCP2 gene among different species. Alignment of the UCP2 genes of pig versus human, showed that there was 86% nucleotide identity between pig and human. There were rich mutation in UCP3 gene, and there was 94% nucleotide identity between Large White and Meishan. The results also showed that the sequence of the partial intron of UCP2 and UCP3, and 3' flanking region of UCP3 existed mutation. The intron 3 was detected by PCR- SSCP analysis, the MDH , adipose cell diameter, average backfat and daily gain were significantly different among of different genotypes in Gansu Black pig. These perhaps associated withtranscriptional factor binding site that were changed from mutation in intron 3 of UCP2.Semi-quantitative RT- PCR was performed to calculate amounts of UCP2 and UCP3 mRNA, relative to the housekeeping gene, - actine. The mRNA levels of UCP2 were lower in the back subcutaneous adipose layer(BA) and the abdominal subcutaneous adipose layer(AA) from Landrance Pig of France line ,a lean meat type, than in those from Large White Pig of Canadian line; the UCP3 mRNA levels were significantly higher in the longissimus muscle from Landrance Pig of France line compared with Large White Pig of Canadian line. These finding suggest that the UCP2 and UCP3 mRNA levels contributes to lean percent and feed convert ratio. The UCP2 mRNA levels were decreased, in contrast to UCP3 mRNA levels were increased in the back subcutaneous adipose layer (BA) and in the longissimus muscle with month age increased.