Characterization of microRNA-Dependent Regulation in C. elegans Germline

Amy Susin
Marquette University
Mentor: Dr. Allison Abbott

It has been shown that worms, fish, and mice cannot live without microRNAs (miRNAs). Thus, miRNAs are essential regulators of gene expression. miRNAs control gene expression by binding to the 3’ UTR of target mRNAs and act to block translation. Currently, there are 112 confidently-identified miRNAs in C. elegans and 475 in humans. It has been estimated that miRNAs may regulate up to 30% of human genes.  However, the specific biological activities of the majority of miRNAs have yet to be discovered. Worms in which the miRNA biogenesis pathway is impaired genetically or by RNAi display germline defects. However, the specific defects in the germline as well as the individual miRNAs that regulate germline development have not been characterized.  To characterize the roles of miRNAs in the germline, we are using RNAi with two closely related Argonaute genes (alg-1 and alg-2), that are essential for miRNA but not siRNA activity, to knock down the miRNA biogenesis pathway in either the whole worm (N2) or in just the germline (rrf-1 mutants).  The rrf-1 gene encodes an RNA-dependent RNA polymerase that is required in the soma (but not in the germline) for the RNAi response. We find that although rrf-1(lf); alg-1/2 (RNAi) animals are fertile, there are possible abnormalities in the proliferative, pachytene, or transition zones of the germline. These observations will be the focus of future work.
 
 

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