Publication Date

Summer 2018

Document Type



Life and Environmental Sciences

First Instructor

Stefanie Otto-Hitt

Experiment Type

Reverse transcriptase (RT) PCR


TTHERM 00142330


Rad51: DNA repair protein RAD51 containing protein; strand exchange protein; involved in homologous recombination and repair of double-stranded DNA breaks


In this experiment, we attempted to answer the question: Does exposure to UV light affect expressionof the Rad51 gene in Tetrahymena thermophila? It was hypothesized that the expression of Rad51 would increase proportionately to the exposure of UV light. The Rad51 protein is fundamental in the repair of double-stranded DNA breaks in eukaryotes, specifically during the process of homologous recombination. In order to test this hypothesis, Tetrahymena were randomly assigned to either a control group, which was cultured under ideal conditions, or a treatment group, which was exposed to UV light. Previous experiments have suggested that T. thermophila prosper most in environments out of direct light and at room temperature. The experimental group was exposed to incremental periods of UV light over the course of 26 hours. Immediately following the culturing and exposure, RNA extraction, reverse transcription, and gene-specific PCR was conducted on the samples from both the control and treatment groups to measure Rad51 expression. Because UV light would likely cause DNA damage and Rad51 plays a role in the repair of such damage, it was predicted that the Rad51 gene would be up-regulated in those organisms exposed to UV light.