Single-oocyte mRNA sequencing reveals that AMH-overexpression alters oocyte gene expression.

Context: Anti-Müllerian hormone (AMH) regulates ovarian follicle development, but AMH overexpression has been linked to impaired fertility and pregnancy failure. Our previous studies indicated that AMH overexpression hindered preimplantation embryo development. Aims: To investigate whether AMH influences oocyte competence, we performed single-oocyte RNA sequencing from wild-type (Thy1.2-AMH0/0) and AMH-overexpressing (Thy1.2-AMHTg/0) mice. Methods: Individual, naturally-ovulated mouse oocytes underwent denuding, followed by preparation of cDNA libraries for sequencing. Thy1.2-AMH0/0 and AMH- Thy1.2-AMHTg/0 oocytes were compared by principle component, differential gene expression and gene ontology analysis. Key results: Principal component analysis revealed that global transcriptomic variation was greater within groups than between groups; however, differential expression analysis identified 39 significantly altered transcripts. The most prominent changes included increased expression of Rps3a3 (70-fold), Hormad1 (22-fold), and Fnip2 (5.6-fold), alongside reduced expression of the ribosomal gene Rps3a. Gene ontology enrichment highlighted mitochondrial function and DNA repair pathways. Our findings suggest that sustained AMH signalling during late folliculogenesis modifies oocyte gene expression. Conclusions: Subtle differences exist between the gene expression profiles of oocytes that develop in an environment with slightly increased AMH levels. Implications: Increased AMH expression may be detrimental to oocyte development.