Publication Date

Summer 2018

Document Type



Life and Environmental Sciences

First Instructor

Stefanie Otto-Hitt

Experiment Type

Reverse transcriptase (RT) PCR


UV radiation


Tfb5: Transcription factor B5 (Tfb5) is a subunit of TFIIH, a basal transcription and DNA repair factor TFIIH.


UVB light is known to cause DNA damage that results in gene mutations. Most regions of DNA damage are corrected using Nucleotide Excision Repair mechanisms (NER). In Drosophila melanogaster, the Tfb5 gene codes for an essential subunit of a protein involved in NER-mediated DNA repair. In this experiment, we attempted to answer the question: will overexpression of the Tfb5 gene in Drosophila compensate for the damage done to DNA by UVB light exposure? In testing this hypothesis, we exposed our Drosophila larvae cultures to 7-minute periods of UVB light once during each stage of larval development. Our control group grew in conditions without UVB light. Larvae counts in both the experimental and control groups served as our quantitative analysis of survivability. Reverse Transcription Polymerase Chair Reaction (RT-PCR) was performed on the extracted larval RNA to determine the level of expressed Tfb5 gene in our control and experimental groups. Because our Drosophila larvae were exposed to UVB light early on in development, we predicted there would be an overexpression of the Tfb5 gene in the experimental group, along with similar numbers of living larvae in both groups.