Molecular genetics on muscle protein metabolism of domestic animal

本研究旨在阐明1)家禽肌肉蛋白质周转率和Calain-calastatin活性的遗传控制，2)calain和calastatin基因的克隆，3)calain和calastatin基因的表达，4)calain基因的定位。人们认识到，鸡和鹌鹑骨骼肌中的肌肉蛋白质周转率随品种和品系的不同而不同，并且与其在骨骼肌中的活性高度相关。在日本黑牛育肥星中，甲基组氨酸的排泄量在不同家系之间存在差异。这一结果表明，不同家系的肌肉蛋白质周转率是不同的。本研究克隆并测序了鹌鹑肌肉钙蛋白基因的全长序列(2112bp)。该基因由4个类似鸡的Domein组成。其序列与鸡、人、鼠和牛的同源性分别为96.8%、71.4%、71.3%和71.6%。虽然不同体型品系在骨骼肌中的表达程度不同，但不同品系之间的表达差异不显著。这些结果表明，不同品系的基因表达差异可能是由激素因素引起的。通过FISH方法，将calain基因定位在3号染色体上。在本研究中，我们无法从鹌鹑肌肉的cDNA中扩增出calastatin片段。

This studies were conducted to clarify 1) genetic control of muscle protein turnover rate and calpain-calpastatin activity of poultry, 2) cloning of calpain and calpastatin genes, 3) expression of calpain and calpastatin genes, and 4) mapping of calpain gene.It was recognized that muscle protein turnover rates differed among breeds and strains, and highly correlated with calpain and calpastatin activities in skeletal muscle of chicken and quail. In the fattening stars of Japanese Black Cattle, the amount of excretion of methylhistidine was differed among sire families. This results suggest that the muscle protein turn over rate are differ among sire families. The cDNA of calpain from muscle of quail was cloned and sequenced (2112bp). The cDNA was composed of 4 domeins like chicken. The identity of quail calpain sequence was 96.8%, 71.4%, 71.3% and 71.6% with chicken, human mouse and cattle., respectively. Although degree of expression of calpain gene in skeletal muscle was differed among quail lines selected for body size, the structure of regulation region of calpain gene were no difference among quail lines. These results suggest that difference in gene expression among quail lines may be caused by hormonal factors. By FISH method, calpain cDNA were mapped on the chromosome No.3. In this research, we could not amplify calpastatin fragment from cDNA of quail muscle.