DNMT3A-dependent DNA methylation is required for spermatogonial stem cells to commit to spermatogenesis

Area of Science:

• Epigenetics
• Reproductive Biology
• Genomics

Background:

• DNA methylation is vital for spermatogenesis, with mutations in DNA methyltransferases (DNMTs) causing male sterility.
• Understanding the specific roles of different DNMTs in germ cells is essential for comprehending male fertility.

Purpose of the Study:

• To elucidate the distinct functions of DNMT3A and DNMT3C in establishing the DNA methylation landscape of male germ cells.
• To investigate the role of DNA methylation in spermatogonial stem cell (SSC) plasticity and differentiation.

Main Methods:

• Single-cell RNA sequencing to reconstruct developmental trajectories.
• Chromatin state profiling to analyze epigenetic modifications.
• Analysis of DNMT mutant mice models.

Main Results:

• DNMT3C is essential for suppressing retrotransposons and ensuring proper meiosis.
• DNMT3A broadly methylates the genome and is critical for SSC differentiation.
• Loss of DNMT3A function in SSCs leads to self-renewal and prevents differentiation due to aberrant enhancer activation.

Conclusions:

• A division of labor exists between DNMT3A and DNMT3C in male germ cells.
• DNMT3A-mediated DNA methylation is key for SSC commitment to differentiation, ensuring lifelong spermatogenesis.
• Epigenetic programming by DNA methylation is fundamental for male fertility.