| Only a fraction of the predicted 19,000 genes in C. elegans has been studied in any detail. With the advent of RNA-mediated interference (RNAi), it is now possible to deplete any protein rapidly without the need for genetic mutations. In combination with the completed genome, we can use RNAi to rapidly assay the functional requirement of almost any predicted gene. In an effort to assign functions to previously uncharacterized genes, I chose to assay the embryonic requirements of maternally expressed transcripts during a collaboration with Fabio Piano. Reinke and colleagues identified 766 ovary-enriched genes via gene chip assays. In addition to testing 350 ovary cDNA clones, I analyzed the functional requirements of 751 ovary-enriched genes using RNAi. Interestingly, I found that fewer than expected numbers of X-linked ovary-expressed genes are essential. Using time-lapse digital microcopy, I recorded the first 50 minutes of development for all of the essential genes. I developed a way to systematically describe the defects observed for each gene in terms of 47-RNAi induced phenotypes. These data were used to group genes into phenoclusters. I find that the phenoclusters correlate well with sequence-based functional predictions indicating they have predictive value.; Through these efforts, I found that the nucleoporin npp-1 is required for spindle rotation in P1 and P0. I have found that four additional nucleoporins (npp-3, npp-4, npp-11, and npp-13) are also required. These nucleoporins all physically interact suggesting that these interactions are important for proper spindle orientation. While the exact nature of this defect is unknown, I propose a model in which the nucleoporins are affecting spindle orientation through an interaction with the dynactin complex. |
