Identification of germline and somatic cell specific genes essential for ovulation in Caenorhabditis elegans.

Abstract

The process of ovulation is an integral part of sexual reproduction in Caenorhabditis elegans. Various genes and signaling pathways are responsible for the successful process of ovulation to occur. Identification of these key mechanisms will help us gain knowledge into the mechanisms underlying the process of ovulation. C. elegans, a free living soil nematode, was used to identify and study the genes that are essential for ovulation. To facilitate this study we have used RNA interference (RNAi), a reverse genetics process, to restrict the function of the genes. RNAi causes degradation of the target gene by introduction of a double stranded RNA which has sequence specificity to the gene of interest. I have analyzed data pertaining to sterile (Ste) phenotype from the previous genome-wide RNAi screens. This search yielded 259 genes which caused Ste phenotype in the wild type background. In this screen, we analyzed 259 genes by RNAi in the wild type and various RNAi resistant mutant backgrounds. A detailed study of the gonad morphology was done to analyze the effect of the depletion of each gene on ovulation. Based on the ability of the mutants to suppress sterility, the genes were categorized as germline or somatic cell specific. In order to study the morphological changes related to gonad arm, we have conducted nomarski microscopy and nuclear staining techniques. Based on our study, 20 genes were categorized as germline specific for ovulation and 9 genes somatic cell specific. Genes that have been identified as germline specific belong to functional classes which code for protein synthesis, gene expression regulation, protein transport and modification, protein degradation, ATP synthesis and RNA specific functional classes. The somatic cell specific genes mainly constitute cell architecture, signaling and other functional groups.