STAT1(Signal transducer and activator of transcription 1)是关系到细胞生长、分化、凋亡和干扰刺激的重要转录因子。PIAS1(Protein inhibitor of activated STAT1)作为STAT1的特异抑制因子,能够阻断STAT1的DNA结合活性,抑制STAT1对于细胞刺激所介导的基因激活。最近几年,关于STAT1和PIAS1的研究已有报到,但在乳腺发育方面研究尚未见报道。试验应用qRT-PCR、Western blotting和免疫组织化学的方法分析STAT1和PIAS1在小鼠乳腺发育的不同时期中的表达情况。结果表明,STAT1和PIAS1的mRNA和蛋白水平从妊娠期到泌乳期都有显著增加,呈协同状态;定位表达结果显示STAT1和PIAS1主要出现在导管上皮细胞以及腺泡上皮细胞上,在乳腺发育的个别时期细胞外基质中有弱表达。从而初步探讨STATI信号转导途径及其负调节因子PIAS1与乳腺发育的关系。
let-7g,a member of the let-7 family,regulates gene expression at the post-transcriptional level.The study explored a series of biological effects of mouse mammary epithelial cells that let-7g was produced.The differential expression of let-7g was detected by qRT-PCR in different developmental stages of the mouse mammary gland.let-7g expression and impact of let-7g on mouse mammary epithelial cells were analyzed by CASY-technology,qRT-PCR,Western blotting and HPLC inhibited let-7g expression of mouse mammary epithelial cells through gene silencing.The results showed that qRT-PCR identified let-7g as being down-regulated in mouse mammary epithelial cells after it was inhibited.Mouse mammary epithelial cells with low expression of let-7g displayed higher expression of TGFβRⅠprotein than those with high expression of let-7g,suggesting that low let-7g expression contributed to TGFβRⅠover-expression.Finally,the expression of let-7g was down-regulated,which significantly enhanced the proliferation of mouse mammary epithelial cells,and increased expression of β-Casein.The data indicated that let-7g could negatively regulate the expression of target Tgfbr1 by complementary combination in mouse mammary epithelial cells,and then regulate the cell proliferation and expression of β-Casein by suppressing the TGFβRⅠexpression.
miRNA can regulate development and milk yield of the mammary gland through epigenetic mechanism.miRNA can directly and indirectly modulate the activity of the epigenetic machinery,target genes through post-inhibition of translation initiation,mediate miRNA decay,target genes and inhibit the positive regulation,regulate tone modification,and regulate DNA methylation of target genes.Here we reviewed the role of miRNAs in mammary gland development and lactation.Researching miRNA in mammary gland development and lactation process,and understanding the response of the epigenetic mechanisms to external stimuli will be an important necessity to devise new technologies for maximizing their activity and milk production in the dairy cow.
