THE POSSIBLE ROLE OF rha-1 IN THE piRNA GENE REGULATORY PATHWAYS IN THE GERMLINE OF Caenorhabditis elegans

Megan Gautier

Date of Award

2013

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Walstrom, Katherine

Keywords

C. Elegans, piRNA, rha-1

Area of Concentration

Biochemistry

Abstract

RNA Helicase A (RHA-1) is a highly conserved protein thought to be involved in the regulation of gene expression within the germline of C. elegans. Previous studies found that mutant nematodes lacking RHA-1 had a temperature sensitive sterility defect similar to those found in mut-7 and rde-2 mutants. The MUT-7 and RDE-2 proteins are known to be involved in 22G-RNA interference, a gene regulation pathway wherein short segments of RNA inhibit the expression of specific target genes. Due to the similar phenotypes noted between these three mutants, it was hypothesized that RHA-1 may also function within the 22G-RNAi pathway, which acts downstream of the recently discovered 21U-piRNA pathway. Double mutants lacking either both RDE-2 and RHA-1 or MUT-7 and RHA-1 were created to explore the effects on the hermaphrodite germline. Preliminary quantification of piRNA-regulated transposons utilizing qRT-PCR revealed that rha-1 mutants did not overexpress the transposons, but RHA-1 activity may be required for the overexpression observed in rde-2 and mut-7 mutants. Through the use of mating assays and microscopy, it was found that when the rha-1 and mut-7 mutations are combined, a previously reported sperm defect within the mut-7 strain is exacerbated such that severe defects in spermatogenesis are observable at lower temperatures. It is thus proposed that RHA-1 may function within regulation of either the initiation of sperm meiosis or in the switch from sperm to oocyte production within the developing hermaphrodite germline.

Rights

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