Identification of novel compound heterozygous ZFP36L2 variants implicated in oocyte maturation defects and female infertility.

Abstract

To explore the pathogenesis of oocyte maturation defects. Whole exome sequencing was conducted to identify potential variants, which were then confirmed within the pedigree through Sanger sequencing. The functional characterization of the identified variants responsible for the disease, including their subcellular localization, protein levels, and interactions with other proteins, was verified through transient transfection in HeLa cells in vitro. Additionally, we employed real-time RT-PCR and single-cell RNA sequencing to examine the impact of ZFP36L2 pathogenic variants on mRNA metabolism in both HeLa cells and mouse or human oocytes. A novel compound heterozygous variant in ZFP36L2 (c.186T > G, p.His62Gln and c.869C > T, p.Pro290Leu) was discovered in a patient with oocyte maturation defects. Our findings indicate that these variants lead to compromised binding capacity of the ZFP36L2-CONT6L complex and impaired mRNA degradation in HeLa cells and mouse oocytes. Furthermore, we characterized the changes in the human oocyte transcriptome associated with ZFP36L2 variants, with a particular emphasis on cell division, mitochondrial function, and ribosome metabolism. This study broadens the mutation spectrum of ZFP36L2 and constitutes the first report of human oocyte transcriptome alterations linked to ZFP36L2 variants. In conjunction with existing knowledge of ZFP36L2, our research lays the groundwork for genetic counseling aimed at addressing female infertility.