CACN-1 is required in the Caenorhabditis elegans somatic gonad for proper oocyte development

CACN-1/Cactin is a conserved protein identified in a genome-wide screen for genes that regulate distal tip cell migration in the nematode Caenorhabditis elegans. In addition to possessing distal tip cells that migrate past their correct stopping point, animals depleted of cacn-1 are sterile. In this study, we show that CACN-1 is needed in the soma for proper germ line development and maturation. When CACN-1 is depleted, sheath cells are absent and/or abnormal. When sheath cells are absent, hermaphrodites produce sperm, but do not switch appropriately to oocyte production. When sheath cells are abnormal, some oocytes develop but are not successfully ovulated and undergo endomitotic reduplication (Emo). Our previous proteomic studies show that CACN-1 interacts with a network of splicing factors. Here, these interactors were screened using RNAi. Depletion of many of these factors led to missing or abnormal sheath cells and germ line defects, particularly absent and/or Emo oocytes. These results suggest CACN-1 is part of a protein network that influences somatic gonad development and function through alternative splicing or post-transcriptional gene regulation.