Ben-Zvi Doreen S, Volk Talila
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
Biol Open. 2019 Mar 5;8(3):bio039842. doi: 10.1242/bio.039842.
Differentiation of germline stem cells (GSCs) in the ovary is induced by somatic escort cells (ECs), which extend membrane protrusions encapsulating the germline cells (GCs). Germline encapsulation requires activated epidermal growth factor receptor (Egfr) signaling within the ECs, following secretion of its ligands from the GCs. We show that the conserved family of irre cell recognition module (IRM) proteins is essential for GC encapsulation by ECs, with a requirement for () and () in the germline and for () and () in ECs. In the absence of IRM components in their respective cell types, EC extensions are reduced concomitantly with a decrease in Egfr signaling in these cells. Reintroducing either activated Egfr in the ECs, or overexpressing its ligand Spitz (Spi) from the germline, rescued the requirement for IRM proteins in both cell types. These experiments introduce novel essential components, the IRM proteins, into the process of inductive interactions between GCs and ECs, and imply that IRM-mediated activity is required upstream of the Egfr signaling.
卵巢中的生殖系干细胞（GSCs）分化由体细胞护卫细胞（ECs）诱导，这些体细胞会伸出膜突起包裹生殖细胞（GCs）。生殖细胞的包裹需要ECs内激活的表皮生长因子受体（Egfr）信号传导，这是在GCs分泌其配体之后发生的。我们发现，不可分割细胞识别模块（IRM）蛋白的保守家族对于ECs包裹GCs至关重要，在生殖细胞中需要（）和（），在ECs中需要（）和（）。在各自细胞类型中缺乏IRM成分时，ECs的延伸会减少，同时这些细胞中的Egfr信号也会降低。在ECs中重新引入激活的Egfr，或者从生殖细胞中过表达其配体斯皮茨（Spi），都能挽救两种细胞类型中对IRM蛋白的需求。这些实验将新型必需成分IRM蛋白引入了GCs和ECs之间的诱导性相互作用过程，并表明IRM介导的活性在Egfr信号传导上游是必需的。
