Dianaliz Santiago-Martínez ALL RIGHTS RESERVED EXPLORING THE FUNCTION OF TRF-1, A TUMOR NECROSIS FACTOR (TNF) RECEPTOR ASSOCIATED FACTOR (TRAF), IN C. ELEGANS POLYCYSTIN- EXPRESSING SENSORY NEURONS

TRAFs are adaptor molecules that function mainly in the immune system. Mammals have seven TRAFs that share a conserved C-terminal domain. The C. elegans genome encodes two TRAF genes, trf-1 and trf-2 (Y110A7A.2). In humans, mutations in the polycystin-1 (PC-1) or polycystin-2 (PC-2) ciliary mechanosensory complex cause ADPKD. In C. elegans, the polycystins LOV-1 and PKD-2 localize to cilia and are required for male sensory behaviors. We find that trf-1 is co-expressed with pkd-2 in the male specific CEM, RnB, and HOB neurons and is required for male mating behaviors. We are interested in exploring a potential connection between immune recognition and mate recognition. We examined the mating behavior of mutant males defective in the Toll pathway including tol-1 and ikb-1. We performed leaving, retention, response, and vulva location (Lov) behavior assays. Like pkd-2 mutants, trf-1(nr2014) mutant males have response and Lov defects. In contrast, tol-1 and ikb-1 are like the wild-type. trf-1 and pkd-2 males are leaving assay (Las) defective, whereas tol-1 is Las but statistically different from pkd-2 and trf-1. ikb-iii 1 males are not Las. All mutant strains are normal for the retention assay, indicating that these males can sense the presence of a mate. We conclude that trf-1 acts like pkd-2, suggesting they function in a similar pathway. The other TRAF gene, trf-2, is also mating defective and seems to act in the same pathway as trf-1. trf-1 and trf-2 act non-redundantly, since the double mutant does not yield a stronger phenotype. To ascertain the site of TRF-1 action, we generated transgenic animals expressing TRF-1::GFP. TRF-1::GFP localizes to cell bodies, dendrites and axons of CEM, HOB and RnB neurons. TRF-1::GFP is detectable in sensory cilia. The mating defects were partially rescued in the mutant. Genetic interactions between TRF-1 and components of the C. elegans PKD pathway (LOV-1, PKD-2, and KLP-6) showed no interaction in yeast two-hybrid experiments. Interestingly, TRF-1 showed interaction with EBAX-1/PQN-55, a substrate recognition subunit for cullin based E3 ligase complex. Ebax-1/pqn-55 males were also shown to be response and location of vulva defective. pqn-55 may act in the PKD pathway as well. iv ACKNOWLEDGEMENT AND DEDICATION