Lin Xianzi, Luo Jun, Zhang Liping, Zhu Jiangjiang
Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China.
Gene Expr. 2013;16(1):1-13. doi: 10.3727/105221613x13776146743262.
Synergistic regulation among microRNAs (miRNAs) is important to understand the mechanisms underlying the complex molecular regulatory networks in goats. Goat milk fat synthesis is driven by a gene network that involves many biological processes in the mammary gland. These biological processes are affected by several miRNAs rather than a single miRNA. Therefore, identifying synergistic miRNAs is necessary to further understand the functions of miRNAs and the metabolism of goat milk fat synthesis. Using qRT-PCR, we assessed the expression of 11 miRNAs that have the potential to regulate milk fat synthesis in the goat mammary gland. Six of these miRNAs exhibited expression during the lactation cycle. Additionally, we also found that prolactin, the key hormone that regulates lactation, promotes the expression of four miRNAs (miR-23a, miR-27b, miR-103, and miR-200a). Further functional analysis showed that overexpression of all four miRNAs by using recombinant adenovirus in goat mammary gland epithelial cells can affect gene mRNA expression associated with milk fat synthesis. Specifically, elevated miR-200a expression suppressed the mRNA expression of genes involved in fat droplet formation. To analyze the synergistic regulation among these four miRNAs (miR-23a, miR-27b, miR-103, and miR-200a), we used the Pearson correlation coefficient to evaluate the correlation between their expression levels in 30 lactating goats. As a result, we found a strong correlation and mutual regulation between three miRNA pairs (miR-23a and miR-27b, miR-103 and miR-200a, miR-27b and miR-200a). This study provides the first experimental evidence that miRNA expression is synergistically regulated in the goat mammary gland and has identified the potential biological role of miRNAs in goat milk fat synthesis. The identification of synergistic miRNAs is a crucial step for further understanding the molecular network of milk fat synthesis at a system-wide level.
微小RNA（miRNA）之间的协同调控对于理解山羊复杂分子调控网络的潜在机制至关重要。山羊乳脂肪合成由一个涉及乳腺中许多生物学过程的基因网络驱动。这些生物学过程受多种miRNA影响，而非单个miRNA。因此，识别协同作用的miRNA对于进一步了解miRNA的功能以及山羊乳脂肪合成的代谢是必要的。我们使用qRT-PCR评估了11种可能调控山羊乳腺中乳脂肪合成的miRNA的表达。其中6种miRNA在泌乳周期中表现出表达。此外，我们还发现催乳素，即调节泌乳的关键激素，可促进4种miRNA（miR-23a、miR-27b、miR-103和miR-200a）的表达。进一步的功能分析表明，通过在山羊乳腺上皮细胞中使用重组腺病毒过表达所有4种miRNA会影响与乳脂肪合成相关的基因mRNA表达。具体而言，miR-200a表达升高会抑制参与脂肪滴形成的基因的mRNA表达。为了分析这4种miRNA（miR-23a、miR-27b、miR-103和miR-200a）之间的协同调控，我们使用皮尔逊相关系数评估了它们在30只泌乳山羊中的表达水平之间的相关性。结果，我们发现三对miRNA（miR-23a和miR-27b、miR-103和miR-200a、miR-27b和miR-200a）之间存在强相关性和相互调控。本研究提供了首个实验证据，证明miRNA表达在山羊乳腺中受到协同调控，并确定了miRNA在山羊乳脂肪合成中的潜在生物学作用。识别协同作用的miRNA是在全系统水平上进一步了解乳脂肪合成分子网络的关键步骤。
