Effects of Ethanol on the Gene Expression of Uracil DNA N-Glycosylase 1 (UNG1) and Growth Rate in Tetrahymena thermophila

Abstract

Alcohol (ethanol) interferes with human health in a variety of ways such as heart damage, liver damage, and specifically, DNA damage. The purpose of this experiment is to explore the effects of ethanol on the growth rate and expression of the uracil DNA N-Glycosylase (UNG1 ) gene in Tetrahymena thermophila. It was hypothesized that expression of UNG1, the gene that codes for the enzyme uracil DNA N-Glycosylase, would increase and that growth rate would decrease in Tetrahymena cells exposed to ethanol. Previous studies suggest that UNG1 expression is increased when DNA is damaged. This enzyme is involved in base excision repair, cutting out the deaminated bases for DNA polymerase to insert the correct base. To test this hypothesis, the experimental group of Tetrahymena cells was exposed to a non-lethal, (1.5%) concentration of ethanol in their growth media for 72 hours. Both the untreated (control) and experimental cultures were maintained under ideal conditions for the 72- hour treatment period and the Tetrahymena cells were counted twice daily to determine growth rate. RNA was subsequently extracted from the control and experimental cultures and Reverse Transcription – quantitative Polymerase Chain Reaction (RT-qPCR) was performed to determine expression of UNG1. It was predicted that ethanol exposure would result in a significant increase in the expression of UNG1 in Tetrahymena and that their growth rate would decrease compared to control cultures.