Vac8-driven vacuolar remodeling primes mega-autophagy and safeguards gamete developmental competence
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During gametogenesis, organelle remodeling is coordinated alongside chromosome segregation to ensure gamete quality. In Saccharomyces cerevisiae , the precursor-cell vacuole permeabilizes following completion of meiotic divisions, releasing hydrolytic enzymes that degrade cellular material excluded from gametes. The regulation and biological significance of this developmentally-programmed process, termed mega-autophagy, remain poorly understood. Here we identify the conserved armadillo repeat-containing protein Vac8 as a key regulator of mega-autophagy. The presence of Vac8 during meiosis is required for timely execution of mega-autophagy. Specifically, during anaphase II, precursor-cell vacuoles undergo Vac8-dependent fusion to form fewer, larger structures. Deleting VAC8 disrupts this remodeling and impairs subsequent vacuolar permeabilization, establishing meiotic vacuolar fusion as a prerequisite for mega-autophagy. Defective mega-autophagy compromises the ability of gametes to exit dormancy and proliferate upon nutrient repletion. Together, these findings reveal that Vac8-mediated vacuolar remodeling during meiosis primes a post-meiotic quality-control mechanism that safeguards gamete developmental competence.
Summary
Xiao et al. show that Vac8 promotes vacuolar fusion during meiosis, priming the vacuole for post-meiotic lysis and clearance of cellular material excluded from gametes. Their findings link meiotic vacuolar remodeling to gamete developmental competence, with implications for germline quality control.
