Document Type

Honors Capstone Project

Date of Submission

Spring 5-1-2007

Capstone Advisor

Dr. Eleanor Maine

Honors Reader

Dr. Melissa Pepling

Capstone Major

Biology

Capstone College

Arts and Science

Audio/Visual Component

no

Capstone Prize Winner

no

Won Capstone Funding

no

Honors Categories

Sciences and Engineering

Subject Categories

Biology

Abstract

My research investigated the relationships among several transcriptional and/or post-transcriptional regulators in the C. elegans germ line. I examined the relationship between the rha-1 gene and three other regulatory genes, ego-1, glp-1 and csr-1. These genes function in germline proliferation and differentiation and are required for fertility. Because these genes regulate similar processes, we have investigated the relationships among them. The rha-1 gene encodes an RNA helicase that is required for germline development, chromatin regulation, and RNA interference (RNAi). The ego-1 gene encodes an RNA-directed RNA polymerase that is also required for these processes. Although many of the rha-1 and ego-1 defects are similar, the rha-1 null phenotype is temperature-sensitive (ts) whereas the ego-1 null phenotype is not. The glp-1 gene encodes a Notch-type receptor that receives an inductive signal from distal tip cell (DTC), which maintains germline proliferation. In the absence of GLP-1 signaling, germ cells that are normally mitotic instead enter meiosis and undergo gametogenesis. The csr-1 gene encodes an Argonaute-type RNA binding protein that is required for germline development and chromatin regulation. Mutations in ego-1 and csr-1 enhance the phenotype of a weak glp-1 mutation. We constructed double mutant strains carrying the rha-1 null allele and either a null allele of ego-1 or csr-1, or a ts allele of glp-1. Our data suggest that EGO-1 and RHA-1 proteins work together to regulate some aspects of development and in parallel to regulate others. Preliminary genetic data also suggest that CSR-1 and RHA-1 work together to regulate development, but act antagonistically to regulate oogenesis onset or a very early step in oogenesis. Additionally, our research suggests that RHA-1 does not regulate germline proliferation by promoting GLP-1 signaling. These findings have improved our understanding of how germline development is regulated in this model organism.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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