RNA interference (RNAi) is a conserved mechanism of gene silencing among eukaryotes, which utilizes noncoding small regulatory RNA molecules (srRNA) to reduce expression of complementary transcripts by several mechanisms. Most known RNAi mechanisms depend on Dicer proteins, which catalyze the production of srRNAs from double-stranded RNA molecules (dsRNA). RNAi in fungi functions primarily in defense of the genome against toxic elements like transposons and transgenes. Additionally, RNAi has functions in growth, sexual development, and response to environmental stresses in some fungi. Though the functions and mechanisms of RNAi have been studied extensively in yeasts and filamentous Ascomycetes, comparatively little research has been done in other clades of fungi, like the mushroom-forming Basidiomycetes. Two genes predicted to encode Dicer-like proteins are present in the genome of the model Basidiomycete Schizophyllum commune. Analysis of mutants lacking these predicted dicer-like genes revealed their involvement in dsRNA-induced RNA silencing, similar to RNAi mechanisms present in other fungi. Mutants lacking either of the dicer-like genes or both genes were able to grow as monokaryons, mate, and develop fruiting bodies capable of producing viable spores, indicating neither gene is essential to the life cycle of S. commune under laboratory conditions. Analysis of the endogenous S. commune transposon SCOOTER failed to identify any transposon movement subsequent to protoplast induction and regeneration stresses in Δdcl mutants when compared to controls. These dicer-like genes may not be involved in control of transposition of SCOOTER, the conditions may not have been sufficient to induce transposition, or other mechanisms may exist to compensate for loss of RNAi.
|Advisor:||Fowler, Thomas J.|
|Commitee:||DiSalvo, Susanne, Luesse, Darron R.|
|School:||Southern Illinois University at Edwardsville|
|School Location:||United States -- Illinois|
|Source:||MAI 57/06M(E), Masters Abstracts International|
|Subjects:||Biology, Molecular biology|
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