Characterizing the proteasomal subunit RPN-6.2 in C. elegans

Abstract

Spermatogenesis is the process whereby sperm cells develop into specialized reproductive cells capable of fertilizing an oocyte. The proteins that tightly regulate sperm cell development are in turn regulated by the ubiquitin proteasome system (UPS). Due to the proteasomes role in regulating meiosis, disruption of the proteasome during spermatogenesis may result in decreased sperm counts and other fertilization defects. We have identified a proteasomal subunit, RPN-6.2, exclusively expressed in sperm. RPN-6.2 surrounds the DNA in spermatids and the motile spermatozoa, while also appearing as dense puncta scattered around the cytoplasm. RPN-6.2 does not localize to membranous organelles or the mitochondria in spermatids or spermatozoa. rpn-6.2 knock-down or RPN-6.2 mutant C. elegans produce less progeny during their reproductive period. rpn-6.2 mutant C. elegans produce fewer sperm suggesting the decrease in progeny may be directly linked to a defect in spermatogenesis caused by dysfunctional proteasome.