Effects of Mos-Kinase inhibition on protein levels during meiosis of starfish oocytes

ABSTRACT: The development of a haploid, fertilizable female gamete involves specialized meiotic divisions of the fully grown oocyte. An essential feature of oocyte meiosis is the reduction of genomic content to half, which is achieved by two successive divisions without an intervening S-phase. A known regulator of this event is a kinase called Mos that is exclusively expressed in oocytes during meiosis and activates the MEK/ERK/MAPK pathway. However, the downstream targets of the Mos-MAPK pathway and their significance in oocyte meiosis remains largely understudied. In this project, using phosphoproteomics on starfish (Patiria miniata) oocytes, we identify two predominant subsets of proteins that are targeted by Mos-MAPK at the critical time point - metaphase of meiosis I. These include proteins involved in CPE-mediated polyadenylation and cytoskeleton regulators. To complement this experiment, we performed DIA proteomics on Mos inhibited (20 micromolar U0126) and control oocytes at subsequent stages of meiosis (at 36 mins, 60 minutes and 90 minutes post hormone addition in U0126 inhibited oocytes and at metaphase I, meiosis I to meiosis II transition, metaphase II, 2 pronuclei and finally at the first mitotic division of the zygote for control oocytes). In this experiment, we identified 7,480 protein groups of which 5,103 protein groups could be quantified. We did not find significant changes in protein abundance across these time points and conditions, indicating that the proteome of starfish oocytes remains largely stable during meiosis.

INSTRUMENT(S): Orbitrap Exploris 480

ORGANISM(S): Patiria Miniata

SUBMITTER: Henning Urlaub   Juliane Liepe   Peter Lenart  

PROVIDER: MSV000098905 | MassIVE | Thu Aug 21 10:49:00 BST 2025

SECONDARY ACCESSION(S): PXD067579

REPOSITORIES: MassIVE