Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China; Joint Laboratory of Modern Agricultural Technology International Cooperation, Ministry of Education, Jilin Agricultural University, Changchun, 130118, China.
Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, China.
Theriogenology. 2020 Jul 15;151:28-40. doi: 10.1016/j.theriogenology.2020.03.030. Epub 2020 Mar 27.
Gremlin genes are known members of the DAN family of bone morphogenetic protein (BMP) antagonists, but their functions and regulatory mechanisms in ovarian follicular development of chicken remain unknown. The current study was designed to investigate the mRNA expression patterns of gremlin1 gene (GREM1) and its protein location in the follicles sampled, and to explore the biological effect of GREM1 on the prehierarchical follicular development. This work revealed that chicken GREM1 mRNA exhibits a constant expression level across all the prehierarchical follicles (PFs) from 1-4 mm to 7-8 mm in diameter, and the preovulatory follicles (from F6 to F1) by using RT-qPCR (P > 0.05). The GREM1 protein is predominantly expressed in the oocytes and granulosa cells (GCs) of the PFs by immunohistochemistry. Furthermore, our data demonstrated that siRNA-mediated knockdown of GREM1 in the GCs resulted in a significant reduction in cell proliferation (P < 0.001); conversely, overexpression of GREM1 in the GCs led to a remarkable increase in cell proliferation (P < 0.001). Interestingly, the expression levels of proliferating cell nuclear antigen (PCNA) and cyclin D2 (CCND2) mRNA and proteins were notably increased when GREM1 expression was upregulated in the GCs (P < 0.01), however, the expression levels of CYP11A1 and StAR were markedly downregulated (P < 0.01). The current results showed that GREM1 gene plays a stimulatory role in GC proliferation during growth and development of the prehierarchical follicles in vitro but an inhibitory role in GC differentiation and steroidogenesis of the hen ovary follicles.
格里mlin 基因是骨形态发生蛋白（BMP）拮抗剂 DAN 家族的已知成员，但它们在鸡卵泡发育中的功能和调节机制尚不清楚。本研究旨在研究 gremlin1 基因（GREM1）的 mRNA 表达模式及其在采样卵泡中的蛋白定位，并探讨 GREM1 对前层级卵泡发育的生物学效应。这项工作表明，通过 RT-qPCR，鸡 GREM1 mRNA 在直径为 1-4mm 至 7-8mm 的所有前层级卵泡（PFs）和预排卵卵泡（从 F6 到 F1）中均表现出恒定的表达水平（P＞0.05）。免疫组织化学显示，GREM1 蛋白主要在 PFs 的卵母细胞和颗粒细胞（GCs）中表达。此外，我们的数据表明，GCs 中 GREM1 的 siRNA 介导敲低导致细胞增殖显著减少（P＜0.001）；相反，GCs 中 GREM1 的过表达导致细胞增殖显著增加（P＜0.001）。有趣的是，当 GCs 中 GREM1 的表达上调时，增殖细胞核抗原（PCNA）和细胞周期蛋白 D2（CCND2）mRNA 和蛋白的表达水平显著增加（P＜0.01），然而，CYP11A1 和 StAR 的表达水平显著下调（P＜0.01）。目前的结果表明，GREM1 基因在体外前层级卵泡生长发育过程中对 GC 增殖起刺激作用，但对 GC 分化和母鸡卵巢卵泡类固醇生成起抑制作用。
