Institute of Pediatrics, Children's Hospital of Fudan University, the Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai 200032, China.
NHC Key Lab of Reproduction Regulation (Shanghai Institute for Biomedical and Pharmaceutical Technologies), Fudan University, Shanghai 200032, China.
Development. 2023 Jun 15;150(12). doi: 10.1242/dev.201572. Epub 2023 Jun 13.
The accumulation and storage of maternal mRNA is crucial for oocyte maturation and embryonic development. PATL2 is an oocyte-specific RNA-binding protein, and previous studies have confirmed that PATL2 mutation in humans and knockout mice cause oocyte maturation arrest or embryonic development arrest, respectively. However, the physiological function of PATL2 in the process of oocyte maturation and embryonic development is largely unknown. Here, we report that PATL2 is highly expressed in growing oocytes and couples with EIF4E and CPEB1 to regulate maternal mRNA expression in immature oocytes. The germinal vesicle oocytes from Patl2-/- mice exhibit decreasing maternal mRNA expression and reduced levels of protein synthesis. We further confirmed that PATL2 phosphorylation occurs in the oocyte maturation process and identified the S279 phosphorylation site using phosphoproteomics. We found that the S279D mutation decreased the protein level of PATL2 and led to subfertility in Palt2S279D knock-in mice. Our work reveals the previously unrecognized role of PATL2 in regulating the maternal transcriptome and shows that phosphorylation of PATL2 leads to the regulation of PATL2 protein levels via ubiquitin-mediated proteasomal degradation in oocytes.
母体 mRNA 的积累和储存对于卵母细胞成熟和胚胎发育至关重要。PATL2 是一种卵母细胞特异性 RNA 结合蛋白，先前的研究已经证实，人类和敲除小鼠中的 PATL2 突变分别导致卵母细胞成熟停滞或胚胎发育停滞。然而，PATL2 在卵母细胞成熟和胚胎发育过程中的生理功能在很大程度上是未知的。在这里，我们报告说 PATL2 在生长卵母细胞中高度表达，并与 EIF4E 和 CPEB1 结合，以调节不成熟卵母细胞中的母体 mRNA 表达。Patl2-/- 小鼠的生发泡卵母细胞表现出母体 mRNA 表达减少和蛋白质合成水平降低。我们进一步证实，PATL2 在卵母细胞成熟过程中发生磷酸化，并使用磷酸蛋白质组学鉴定了 S279 磷酸化位点。我们发现 S279D 突变降低了 PATL2 的蛋白水平，并导致 Palt2S279D 敲入小鼠的生育力下降。我们的工作揭示了 PATL2 以前未被认识的在调节母体转录组中的作用，并表明 PATL2 蛋白水平的磷酸化通过卵母细胞中的泛素介导的蛋白酶体降解来调节 PATL2 蛋白水平。
