The formation of a complex organ requires multiple developmental processes that must each be properly executed and also coordinated with one another. Investigating the cellular and molecular basis of these 3rocesses provides important insight into normal developmental mechanisms that will expand our understanding of developmental defects and contribute to progress in culturing tissues and organs for medical use. Furthermore, as many diseases result from a normal cellular process gone awry, basic developmental biology research provides key insights into disease initiation, progression, and potential treatments. This proposal is focused on elucidating the role of the Caenorhabditis elegans NUD-1 protein and functionally-related proteins in the development of a specific organ, the gonad. The gonad is a well established model system for studying organogenesis, however, many features of gonad formation are not understood. NUD-1 is a well conserved, but novel protein that provides an inroad into less understood aspects of C. elegans gonadogenesis. First, the gonadal phenotype associated with depletion of NUD-1 will be determined using two distinct approaches. NUD-1 knock-down mutants will be generated using the reverse genetic approach of RNA-mediated interference (RNAi) and characterized using cell-type specific markers. To allow study of the primary gonadal defect associated with loss of NUD-1, a genetic screen will be performed in an attempt to obtain a heritable nud-1 mutation. The second aim is to characterize the gonadal expression pattern of NUD-I. Again, a two-pronged approach will be employed and both NUD- 1::GFP expression constructs and a NUD-l-specific antibody will be generated and analyzed. Finally, other mutations with a Nud phenotype will be identified in the genetic screen and characterized. Experiments will be performed to determine if the newly identified loci function with nud-1, or with each other, in gonad development. Overall, the proposed work is designed to increase our knowledge of mechanisms used in organ formation and to shed light on the means by which NUD-1 exerts its effects. [unreadable] [unreadable] [unreadable]