Caryn Wolter

The Drosophila melanogaster Trus is an ortholog to the human PDCD2L and is believed to similarly play a role in the biogenesis and nuclear export of the 40S ribosomal subunit, therefore influencing protein translation and the cell cycle. trus mutant in Drosophila shows a significant developmental delay and lethality during larval stage, however, the mechanism that causes the defects is not understood. Human PDCD2L protein was shown to shuttle between the nucleus and cytoplasm in a CRM1-dependent manner. We have shown that EGFP-Trus expressed in S2 cells primarily localizes to the cytoplasm. However, nuclear retention was found after treating the cells with Leptomycin B, an inhibitor of CRM1-dependent nuclear export. To further elucidate the molecular function of Trus in the cell and during development, we are generating single and multiple site mutations among nine NES candidate sites to identify functional NES, with an aim to express a nuclear export-deficient Trus molecule in vivo and investigate whether the nuclear-cytoplasmic shuttling of Trus is important for its developmental function. We also performed phenotypic analysis of trus mutant larval tissues. Preliminary data indicates that the size of the larval brain was reduced compared to the wild-type brain. The wing discs also show morphological abnormalities. Further analysis of tissues stained with mitotic and apoptotic markers will help elucidate the molecular mechanism of these developmental defects.