Sperm-contributed centrioles segregate stochastically into blastomeres of 4-cell stage C. elegans embryos

Abstract

Whereas both sperm and egg similarly contribute nuclear genetic material to the zygote of metazoan organisms, the inheritance of other cellular constituents is unequal between the two gametes. Thus, the centriole organelle is contributed solely by the sperm to the zygote in most systems. Whereas centrioles can have a stereotyped distribution during some asymmetric divisions, whether sperm-contributed centrioles are distributed in a stereotyped manner in the resulting embryo is not known. Here, we addressed this question in Caenorhabditis elegans using marked mating experiments, whereby the presence of sperm-contributed centrioles is monitored in the resulting embryos using the stable centriolar component SAS-4::GFP, as well as GFP::SAS-7. Our analysis demonstrates that the distribution of sperm-contributed centrioles is stochastic in 4-cell stage embryos. Moreover, using sperm from zyg-1 mutant males that harbor a single centriole, we show that the older sperm-contributed centriole is also distributed stochastically in the resulting embryo. Overall, we conclude that in contrast to the situation during some asymmetric cell divisions, centrioles contributed by the male germ line are distributed stochastically in embryos of C. elegans.