Examining the role of RNAi in developmental pathways in C. elegans

The ability of RNA interference (RNAi) to regulate gene expression through multiple pathways shows the true complexity and diversity of these processes. To examine this complexity, I studied different genes to determine if they were necessary for specific RNAi pathways as well as male tail development. D1037.1, a dsRNA binding protein, was examined to determine whether it was necessary for transgene induced silencing using a gfp construct. I also examined the possible role that pal-1, rrf-1, rrf-3, and hpl-2, genes all necessary for some RNAi pathways, may have in male Caenorhabditis elegans tail development. pal-1 is a Hox gene that has been shown to be necessary for normal tail development in C. elegans. In pal-1 mutant worms, the resulting phenotype is almost complete loss of V6 sensory rays. rrf-1 and rrf-3, both encode RNA dependent RNA polymerases. I examined the interaction of rrf-1 and rrf-3 by crossing both genes into a pal-1 mutant background to examine whether either gene could suppress pal-1, resulting in normal tail development. I determined that rrf-1 and rrf-3 do not suppress the pal-1 mutation. The last gene that I examined was hpl-2, a gene that plays a role in chromatin stability and normal development and growth in C. elegans to observe whether it participated in male tail development. I determined that mutations in hpl-2 enhances the pal-1 mutant phenotype. This research helps show the complexity and diversity of RNAi and its related silencing pathways. The role of these genes in male tail development may not solely be depenendent on the double stranded RNA (dsRNA) pathway but also possibly tiny non-coding RNA, pre- X cluster and ORF pathways as well