The gonadal sheath of Caenorhabditis elegans is essential to the correct development of male and female gametes. The gonadal sheath and the distal tip cell (DTC) play an essential role in germ line proliferation, and the gonadal sheath additionally is vital for germ cell fate specification, meiotic progression from pachytene and ovulation of oocytes into the spermatheca. The absence of a gonadal sheath results in reproductive disorders such as sterility. Double stranded RNA interference (dsRNAi), the process by which homologous double-stranded RNA is introduced to a cell and interferes with the expression of a gene, was employed to determine the genes essential to the gonadal sheath. Strains DG1575 tnIs6[
lim-7::GFP, Rol-6
(su1006)] (kind gift of D. Greenstein) and GC678 tnIs5[
lim-7::GFP; Rol-6
(su1006)]; qIs19[
lag-2::GFP, Rol-6
(su1006)] (kind gift of E. J. A. Hubbard), each carrying a GFP reporter system that auto-fluoresces in the gonadal sheath (and the DTC in GC678) were utilized to assess genes essential for gonadal sheath production in a dsRNAi screen. Hermaphrodites from either of these strains were fed bacteria containing individual dsRNAi clones to examine the requirement of genes on Chromosomes I and II for development of the gonadal sheath. Hermaphrodites exposed to individual dsRNAi clones were examined for loss of gonadal sheath tissue as assessed by loss of GFP fluorescence and consequent sterility. To date, we have screened all the genes on Chromosome I and the majority of the genes on Chromosome II. Progress and subsequent findings will be reported.