Molecular Mechanisms of Spermatogenesis in Mammalian Germ Cells

Spermatogenesis in mammals is a highly orchestrated process in which diploid spermatogonia undergo mitotic proliferation, meiotic division and terminal differentiation to produce haploid spermatozoa. At the molecular level, this involves precise temporal control of transcription, RNA processing, chromatin remodelling and post-transcriptional regulation. Initiation of meiosis requires programmed double-strand breaks and homologous recombination, while dynamic histone modifications and replacement by protamines drive chromatin condensation in elongating spermatids. RNA-binding proteins, small noncoding RNAs and specialised ribonucleoprotein granules coordinate the storage, localisation and translational activation of key transcripts in transcriptionally silent stages. Ubiquitin-mediated proteolysis and endoplasmic reticulum quality control ensure protein homeostasis during germ cell maturation. Phosphorylation of RNA helicases and the regulated pausing of RNA polymerase II further refine germ-cell-specific gene expression programmes. Disruption of any of these mechanisms can lead to spermatogenic arrest, impaired sperm function and male infertility, underscoring the global significance of understanding these pathways for reproductive health and potential therapeutic intervention.

Research from Nature Portfolio

Recent studies have uncovered a critical requirement for promoter-proximal pausing of RNA polymerase II during the earliest stages of spermatogonial differentiation. Loss of the pause-inducing factor NELF in immature germ cells abolishes progression to spermatids, revealing that stabilisation of paused polymerase shapes the developmental landscape of meiotic and post-meiotic gene expression. Moreover, paused polymerase complexes appear to mark sites of programmed double-strand breaks, coupling transcriptional control to the initiation and repair of meiotic recombination events. These findings illuminate pausing as a central node linking transcriptional regulation to genome integrity in male germ cell development.

Molecular Mechanisms of Spermatogenesis in Mammalian Germ Cells publication trend

The graph below shows the total number of articles in molecular mechanisms of spermatogenesis in mammalian germ cells across all publications each year (not limited to Nature Index journals).

Technical terms

RNA polymerase II pausing: Temporary stalling of the polymerase at promoter-proximal sites to regulate gene activation timing.

NELF (negative elongation factor): A protein complex that induces and stabilises RNA polymerase II pausing.

microRNA (miRNA): Small noncoding RNA molecules that guide post-transcriptional repression of target mRNAs.

mRNA uridylation: Addition of uridine residues to the 3′ end of mRNA, marking transcripts for degradation.

Spermiogenesis: Final phase of spermatogenesis in which round spermatids elongate, condense chromatin and form mature spermatozoa.

References

1. RNA polymerase II pausing is essential during spermatogenesis for appropriate gene expression and completion of meiosis. Nature Communications (2024).
2. miRNA Expression Profiles of Mouse Round Spermatids in GRTH/DDX25-Mediated Spermiogenesis: mRNA–miRNA Network Analysis. Cells (2023).
3. Single-Cell Transcriptomic Profiling of the Mouse Testicular Germ Cells Reveals Important Role of Phosphorylated GRTH/DDX25 in Round Spermatid Differentiation and Acrosome Biogenesis during Spermiogenesis. International Journal of Molecular Sciences (2023).
4. A programmed wave of uridylation-primed mRNA degradation is essential for meiotic progression and mammalian spermatogenesis. Cell Research (2019).