Monocarboxylate transporter genes in the mammary gland of lactating cows
Monocarboxylate transporter genes in the mammary gland of lactating cows
复制标题
DOI：
10.1007/s00418-009-0621-1
复制
发表时间：
2009-07
影响因子：
2.3
通讯作者：
D. Kirat;S. Kato
中科院分区：
文献类型：
--
作者：
D. Kirat;S. Kato
本研究首次检测了14个单羧酸转运蛋白基因（MCT 1-MCT 14）在哺乳动物乳腺中的表达。采用RT-PCR、Western blot、免疫组织化学和免疫荧光共聚焦激光显微镜技术，综合评估泌乳牛乳腺中MCT的表达和细胞定位。RT-PCR结果显示，奶牛乳腺中存在9种MCT异构体，即MCT 1、MCT 2、MCT 3、MCT 4、MCT 5、MCT 8、MCT 10、MCT 13和MCT 14。扩增的cDNA片段经序列分析证实，并在GenBank中保存。使用市售的抗MCT 1-MCT 8抗体，Western印迹法验证了奶牛乳腺中MCT 1、MCT 2、MCT 3、MCT 4、MCT 5和MCT 8的蛋白表达。所鉴定的MCT蛋白的精确细胞定位表明，MCT 1和MCT 2均位于奶牛乳腺肺泡上皮细胞的基底外侧。相反，MCT 4蛋白信号在这些肺泡上皮细胞的顶膜上表达。然而，MCT 8主要定位在乳细胞的基底外侧膜上，并且沿着其在相同细胞的顶膜上的弱标记。在泌乳牛乳腺组织中未检测到MCT 3和MCT 5蛋白的免疫反应性染色。此外，我们证明了CD 147与MCT 1和MCT 4在奶牛乳腺肺泡上皮细胞边界上的共定位。MCT基因在泌乳奶牛乳腺中的存在和定位模式表明它们可能参与乳汁合成和分泌所需必需元素的转运。
This study is the first to examine the expression of the 14 monocarboxylate transporter genes (MCT1–MCT14) in the mammary gland of mammals. RT-PCR, Western blot, immunohistochemistry, and immunofluorescence confocal laser microscopy were applied in a comprehensive approach to assess the expression and cellular localization of MCTs in the mammary gland of lactating cattle. RT-PCR revealed the existence of nine MCT isoforms, namely MCT1, MCT2, MCT3, MCT4, MCT5, MCT8, MCT10, MCT13, and MCT14 in cow mammary gland. The amplified cDNA segments were confirmed by sequence analysis and deposited in the GenBank. Using the commercially available antibodies against MCT1–MCT8, Western blotting verified the protein expression of MCT1, MCT2, MCT3, MCT4, MCT5, and MCT8 in the cow mammary gland. The precise cellular localization of the identified MCT proteins showed that both MCT1 and MCT2 were basolaterally localized on the cow mammary alveolar epithelial cells. In contrast, MCT4 protein signal was expressed on the apical membrane of these alveolar epithelia. MCT8, however, was predominantly localized on the basolateral membranes of the lactocytes, along with its weak labeling on the apical membrane of the same cells. No immunoreactive staining for MCT3 and MCT5 proteins could be detected histochemically in lactating bovine mammary tissue. Additionally, we proved the colocalization of CD147 with both MCT1 and MCT4 on the boundaries of the cow mammary alveolar epithelia. The existence and localization pattern of MCT genes in the mammary gland of lactating cows suggest their possible involvement in the transport of essential elements required for milk synthesis and secretion.