BMPR-1B is part of the transforming growth factor β super family and plays a pivotal role in ewe litter size. Functional loss of exon-8 mutations in the BMPR-1B gene (namely the FecB gene) can increase both the ewe ovulation rate and litter size. This study constructed a eukaryotic expression system, prepared a monoclonal antibody, and characterized BMPR-1B/FecB protein–protein interactions (PPIs). Using Co-immunoprecipitation coupled to mass spectrometry (Co-IP/MS), 23 proteins were identified that specifically interact with FecB in ovary extracts of ewes. Bioinformatics analysis of selected PPIs demonstrated that FecB associated with several other BMPs, primarily via signal transduction in the ovary. FecB and its associated interaction proteins enriched the reproduction process via BMP2 and BMP4 pathways. Signal transduction was identified via Smads proteins and TGF-beta signaling pathway by analyzing the biological processes and pathways. Moreover, other target proteins (GDF5, GDF9, RhoD, and HSP 10) that interact with FecB and that are related to ovulation and litter size in ewes were identified. In summary, this research identified a novel pathway and insight to explore the PPi network of BMPR-1B.

中文翻译：

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真核表达、Co-IP 和 MS 识别 BMPR-1B 蛋白质-蛋白质相互作用网络。

BMPR-1B 是转化生长因子 β 超家族的一部分，对母羊产仔数起着关键作用。BMPR-1B 基因（即 FecB 基因）外显子 8 突变的功能丧失可增加母羊排卵率和窝产仔数。本研究构建了真核表达系统，制备了单克隆抗体，并表征了 BMPR-1B/FecB 蛋白-蛋白相互作用 (PPI)。使用免疫共沉淀与质谱联用 (Co-IP/MS)，鉴定出 23 种与母羊卵巢提取物中的 FecB 特异性相互作用的蛋白质。对所选 PPI 的生物信息学分析表明，FecB 主要通过卵巢中的信号转导与其他几种 BMP 相关联。FecB 及其相关的相互作用蛋白通过 BMP2 和 BMP4 途径丰富了繁殖过程。通过分析生物过程和通路，通过 Smads 蛋白和 TGF-β 信号通路鉴定信号转导。此外，还鉴定了与 FecB 相互作用并与母羊排卵和产仔数相关的其他靶蛋白（GDF5、GDF9、RhoD 和 HSP 10）。总之，本研究确定了探索 BMPR-1B 的 PPi 网络的新途径和见解。