Affiliation:
1. The Innovation Centre of Ministry of Education for Development and Diseases, the Second Affiliated Hospital, School of Medicine South China University of Technology Guangzhou China
2. Center for Sleep and Circadian Medicine The Affiliated Brain Hospital of Guangzhou Medical University Guangzhou China
Abstract
AbstractEukaryotic translation initiation factor 2 subunit 2 (EIF2S2), a subunit of the heterotrimeric G protein EIF2, is involved in the initiation of translation. Our findings demonstrate that the depletion of Eif2s2 in premeiotic germ cells causes oocyte arrest at the pachytene and early diplotene stages at 1 day postpartum (dpp) and 5 dpp, respectively, and eventually leads to oocyte apoptosis and failure of primordial follicle formation. Further studies reveal that Eif2s2 deletion downregulates homologous recombination‐related and mitochondrial fission‐related protein levels, and upregulates the integrated stress response‐related proteins and mRNA levels. Consistently, Eif2s2 deletion significantly decreases the expression of dictyate genes and compromises mitochondrial function, characterized by elongated shapes, decreased ATP levels and mtDNA copy number, along with an excessive accumulation of reactive oxygen species (ROS) and mitochondrial superoxide. Furthermore, DNA damage response and proapoptotic protein levels increase, while anti‐apoptotic protein levels decrease in Eif2s2‐deleted mice. An increase in oocytes with positive cleaved‐Caspase‐3 and TUNEL signals, alongside reduced Lamin B1 intensity, further indicates oocyte apoptosis. Collectively, Eif2s2 deletion in premeiotic germ cells causes oocyte meiotic arrest at the early diplotene stage by impairing homologous recombination, and eventually leads to oocyte apoptosis mainly through the downregulation of mitochondrial fission‐related proteins, ROS accumulation and subsequent DNA damage.
Funder
National Key Research and Development Program of China
National Natural Science Foundation of China