RNAi screen for novel components in Caenorhabditis elegans ovulation and fertility.

Abstract

The intercellular and intracellular signaling pathways elucidated through research on the nematode C. elegans provide valuable information on the communication systems throughout all organisms. Through the use of RNA interference (RNAi), it is possible to discover additional genes that may play roles in signaling pathways. The inositol trisphosphate (IP₃) signaling pathway maintains the basal and ovulatory contractions of the sheath cells in all C. elegans organisms. Utilizing an RNAi feeding protocol to knock down expression of genes, some 155 genes capable of causing sterility in wild-type C. elegans were identified. Focusing on these contractions of the sheath cells through control of the IP₃ signaling pathway, a mutant C. elegans for the IP₃ receptor, itr-1(sy290), was used. The ITR-1 receptor, located on the endoplasmic reticulum, normally allows for the release of calcium ions when IP₃ binds, and is constitutively active in the itr-1(sy290) mutant worm. The mutant itr-1(sy290) worms maintain higher concentrations of cytoplasmic calcium, which resulted in a rescue of the sterility seen in the wild-type worms in this study. Due to the potential for pleiotropic effects of many of these sterility causing genes, we looked for known components of the IP₃ signaling pathway (eg. plc-3) and at their sterility scores, as well as the scores most comparable to these known components. This reduced the gene pool down to 24 significant genes. Examination of these genes reveals a wider communication network necessary for proper ovulation in C. elegans.