ALKB-1-dependent tRNA methylation is required for efficient paternal mitochondrial elimination

Area of Science:

• Epigenetics and Developmental Biology
• Mitochondrial Biology
• Reproductive Science

Background:

• Maternal inheritance of mitochondria relies on eliminating paternal mitochondria.
• The role of epigenetic modifications in paternal mitochondrial elimination (PME) is not well understood.
• Understanding PME is key to reproductive success and preventing mitochondrial diseases.

Purpose of the Study:

• To investigate the role of epigenetic modifications in paternal mitochondrial elimination (PME).
• To identify key factors regulating mitochondrial quality control during reproduction.
• To elucidate the mechanisms underlying the inheritance of mitochondria.

Main Methods:

• Utilized Caenorhabditis elegans (C. elegans) as a model organism.
• Investigated the function of the DNA/RNA demethylase ALKB-1 in PME.
• Analyzed the impact of ALKB-1 on tRNA m1A methylation, protein translation, mitochondrial proteostasis, and ROS levels.
• Examined the activation of oxidative stress response (SKN-1/Nrf2) and mitochondrial unfolded protein response (UPRmt) pathways.

Main Results:

• ALKB-1 is essential for efficient paternal mitochondrial elimination (PME).
• ALKB-1 inactivation causes tRNA m1A hypermethylation, disrupting protein translation and mitochondrial proteostasis.
• Impaired PME leads to increased ROS, activation of SKN-1/Nrf2 and UPRmt, and accumulation of mitochondria and mtDNA in sperm.
• Defects in PME negatively affect male fertility and embryonic development.

Conclusions:

• ALKB-1-mediated tRNA m1A epitranscriptomic modifications are critical for mitochondrial quality control and PME.
• This epitranscriptomic stress checkpoint ensures proper mitochondrial inheritance during reproduction.
• Dysregulation of ALKB-1 impacts male fertility and embryonic outcomes, highlighting its importance in reproductive health.