L型氨基酸转运载体1对奶牛乳腺中β-酪蛋白表达的影响

为研究L型氨基酸转运载体1（L type amino acid transporter 1，LAT1）对奶牛乳腺中β-酪蛋白表达的作用，本试验采用PCR技术体外扩增奶牛LAT1基因并构建LAT1真核表达载体，采用脂质体转染技术将LAT1真核表达载体转染奶牛乳腺上皮细胞，并于转染48 h后采用Western blotting技术检测LAT1过表达后乳腺上皮细胞中LAT1、4F2hc和β-酪蛋白的表达变化。荧光显微镜检测结果显示，LAT1真核表达载体成功转染奶牛乳腺上皮细胞；Western blotting检测结果显示，LAT1过表达的奶牛乳腺上皮细胞中LAT1极显著增加（P<0.01），β-酪蛋白的表达显著升高（P<0.05），4F2hc表达变化不显著（P>0.05）。这些结果提示LAT1对奶牛乳腺上皮细胞乳蛋白合成具有促进作用。

Effect of L Type Amino Acid Transporter 1 on β-casein Expression in Mammary Epithelial Cells of Dairy Cows

In order to investigate the effect of LAT1 on β-casein expression in mammary epithelial cells of dairy cows,the LAT1 gene of dairy cow was amplified by PCR and pIRES2-EGFP-LAT1 expression vector was constructed.Then pIRES2-EGFP-LAT1 expression vector was transfected into mammary epithelial cells.The effects of LAT1 overexpression on expression of LAT1,4F2hc and β-casein were detected by Western blotting after 48 h of transfection.The results showed that pIRES2-EGFP-LAT1 was transfected into mammary epithelial cells successfully.The expression of LAT1 was extremely significantly increased (P<0.01) and β-casein was significantly increased (P<0.05) when LAT1 was overexpressed,while the expression of 4F2hc was not significantly changed (P>0.05).These results suggested that LAT1 had an important role in promoting milk protein synthesis in mammary epithelial cells of dairy cow.