An Analysis of Putative Roles for the CCR4-NOT Deadenylase-Complex Subunit Regena (NOT2) in microRNA-Mediated Gene Silencing in \u3cem\u3eDrosophila Melanogaster\u3c/em\u3e

microRNAs (miRNAs) are one class of small non-coding ribonucleic acid (RNA) molecules essential to development and homeostasis in plants and animals. miRNAs silence gene expression through complementary base pairing with target gene messenger RNAs and association with the miRNA-induced silencing complex (miRISC). The identification and characterization of cellular factors required for miRNA-mediated gene silencing is incomplete. A forward genetic screen was carried out in Drosophila melanogaster to generate flies defective for gene silencing. Silencing was assayed by expression of a Green Fluorescent Protein (GFP) reporter fused to the Brd gene 3’ UTR, which is regulated by miRNAs. Genetic analysis revealed that the CCR4-NOT deadenylase-complex subunit Regena (NOT2) is required for miRNA-mediated silencing of the reporter. In addition, perturbation of Regena function altered Drosophila eye development and resulting adult eye morphology. miRNAs are thought to silence target gene expression through a combination of translational repression and target mRNA degradation, though the detailed mechanism of this process is a matter of controversy. Novel genetic reagents to explore miRNA function in vivo have been generated and characterized. Ongoing efforts aim to explore whether Regena is required to silence other miRNA targets in vivo, and whether Regena is required for miRNA-mediated gene silencing at different stages of the Drosophila life cycle. Elucidation of the lesion in the Regena (NOT2) gene and the molecular nature of GFP reporter silencing will contribute to an understanding of the mechanism of miRNA-mediated gene silencing in vivo