Abstract
The Caenorhabditis elegans distal tip cells (DTCs) are an in vivo model for the study of developmentally regulated cell migration. In this study, we characterize a novel role for CCDC-55, a conserved coiled-coil domain containing protein, in DTC migration and larval development in C. elegans. Although animals homozygous for a probable null allele, ccdc-55(ok2851), display an early larval arrest, RNAi depletion experiments allow the analysis of later phenotypes and suggest that CCDC-55 is needed within the DTC for migration to cease at the end of larval morphogenesis. The ccdc-55 gene is found in an operon with rnf-121 and rnf-5, E3 ubiquitin ligases that target cell migration genes such as the β-integrin PAT-3. Genetic interaction studies using RNAi depletion and the deletion alleles rnf-121(ok848) and rnf-5(tm794) indicate that CCDC-55 and the RNF genes act at least partially in parallel to promote termination of cell migration in the adult DTC.