DigitalCommons@Linfield

Investigation of a Putative Role for the Protein Kinase TOR (Target of Rapamycin) in microRNA-Mediated Gene Silencing in Drosophila Melanogaster

Jereld R. Nicholson Library

miRNAs are small non-coding RNA molecules that regulate gene expression. miRNAs bind via complementary base paring to target messenger RNAs (mRNAs) and recruit the miRNA-specific RNA-Induced Silencing Complex (miRISC) to induce target gene silencing by translation block or target mRNA degradation. Many aspects of miRNA regulation and downstream effector function have not been elucidated. Previous work utilized a Green Fluorescent Protein (GFP)-based sensor to visualize miRNA function and facilitate the isolation of mutants defective for miRNA-mediated gene silencing. Subsequent genetic analysis revealed a role for components of the insulin-signaling pathway in miRNA-mediated gene regulation. Ongoing efforts aim to evaluate the putative role of the protein kinase TOR (target of rapamycin) in miRNA-mediated gene silencing. TOR integrates signals from numerous cell-signaling pathways, responding to the presence of insulin, growth factors and amino acids, yet it is not known whether TOR is essential for miRNA function. This question is being addressed by evaluating the silencing of the GFP reporter of miRNA function in Drosophila eye tissue that lacks functional TOR. FLP/FRT-mediated mitotic recombination is being utilized to generate homozygous clones of cells in the Drosophila eye that lack functional TOR, so that sensor silencing can be evaluated in comparison to wild type tissue marked by the Red Fluorescent Protein (RFP). Sensor assays are being carried out in 3^rd instar eye imaginal discs to avoid complications arising from the expression of the mini-white gene in adult eyes. Preliminary results suggest that miRNA-mediated gene silencing is altered in the absence of functional TOR.