Identification RBPMS2 as a key regulator in mouse early oocyte development

In the process of follicle formation, oocyte stably maintain large number of RNAs for development. However, how mammalian oocytes regulate these mRNAs, especially in the early oocyte, is unclear. We focused on RNA-binding proteins and identified RBPMS2 as a key factor in this process. Genetic disruption Rbpms2 causes female mouse infertility due to primordial oocyte defect. Transcriptome and RIP-seq analysis revealed that RBPMS2 binds 3' UTR region to stabilize mRNAs of known oogenesis regulators, such as Lhx8. RBPMS2 also targets transcripts regulating cytoskeleton and cellular trafficking, such as Clasp1 and Rab27a, which are down-regulated in knock out oocytes. Rbpms2 knock out induces impairments in endocytosis and the accumulation of mitochondria and Golgi bodies in primordial oocyte. In summary, our study reveals RBPMS2 regulates mouse oogenesis through stabilizing mRNAs regulating oocyte development cellular trafficking and organelle enrichment, connecting post-transcriptional regulation to organelles accumulation and early oocyte development. Overall design: P1 ovaries of wild type or Rbpms2 knock out mice are digested with collagenase (2mg/ml) at 37°C for 5-10 minutes. Remove the collagenase and digest the ovaries with trypsin (0.25%) at 37°C for 5-10 minutes, and then pipette gently to dissociate into single cells. FBS is added to stop the reaction and cells are collected by centrifugation (500g, 5-10 min). Resuspend the cells in PBS. Five to ten putative primordial oocytes per group were collected by a mouth pipette into one tube for mRNA amplification which was performed following the manufacturer's instructions (Vazyme, N712-03) with 18 amplification cycles. Library preparation followed the methods in (Chen et al., 2023). Briefly, after test the concentration by Qubit Flex Fluorometer (Thermo Fisher Scientific) and fragment size by Agilent Bioanalyzer 2100, TruePrep DNA Library Prep Kit V2 for Illumina (Vazyme, TD503) was used to prepare the library.