Grace Bacon

Date of Award

2015

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Walstrom, Katherine

Keywords

Argonaute Proteins, RNA, C. elegans, ALG-3, ALG-4

Area of Concentration

Chemistry

Abstract

Argonaute proteins have been well established as key players in RNA interference. In recent years, argonautes have been shown to play a role in the upregulation of particular gene targets. In C. elegans, spermatogenesis is a thermosensitive process. The argonaute proteins ALG-3 and ALG-4 have been shown to upregulate certain spermatogenesis genes at elevated temperatures, allowing for the production of functional sperm at these temperatures (Conine et al. 2010). Deletion mutants in RNA Helicase A (rha-1) have similar phenotypes as alg-3/4 mutants, including the production of sterile worms at elevated temperatures. This project sought to understand whether a connection may exist between RHA-1 and ALG-3/4. This was achieved using immunofluorescence assays of spermatocyte features previously identified as changed in male alg-3/4 mutants (Conine et al. 2013). Between the control strain (him-8) and the two mutant strains (alg-3/4 and rha-1), both features (MSP expression and H3K4 dimethylation) were consistently changed. The changes in MSP expression were complicated and not statistically significant. H3K4 dimethylation was shown to be statistically significantly (α<0.05) underexpressed in both alg-3/4 and rha-1 mutant spermatocytes as compared to him-8 spermatocytes. These results were replicable across two procedures of immunofluorescence. H3K4 dimethylation is a common activating histone modification. Thus, it is reasonable to conclude that the increased presence of H3K4me2 in the control samples aids in the upregulation by ALG-3/4 and possibly by RHA-1. Given the wide range of similarities between the effects of the two proteins on the sperm of C. elegans, it is likely that RHA-1 plays a role in the ALG-3/4 RNA interference pathway.

Download

Share

COinS