eEF1G Orchestrates Translation to Ensure Meiotic Progression in Transcriptionally Quiescent Spermatocytes

During meiotic prophase I, mammalian spermatocytes must synthesize large amounts of recombination and synapsis proteins despite global transcriptional suppression at the leptotene/zygotene (L/Z) stages. Here, we identify eukaryotic translation elongation factor 1 gamma (eEF1G), highly expressed in spermatogenic cells, as a factor essential for sustaining translation during this transcriptionally quiescent period. Germ cell-specific Eef1g knockout causes complete male infertility due to zygotene arrest, characterized by defects in recombination intermediate stabilization and synapsis. Mechanistically, eEF1G associates with ribosomal proteins, and ribosome profiling reveals increased ribosome occupancy on specific meiotic transcripts in Eef1g-deficient spermatocytes. Quantitative proteomics further reveals selective depletion of synapsis-related (e.g., SYCP1, SYCE1) and recombination-related proteins (e.g., MSH4, TEX11). Together, these findings demonstrate that eEF1G is required to maintain efficient protein production during the transcriptionally quiescent leptotene/zygotene stages, thereby supporting proper meiotic progression in mammalian spermatocytes.