Talk abstracts

Talk on Friday 08:10-08:30pm submitted by Peter Palenchar

The Effect of Oxidative Stress on the Levels of tRNA Modifications

Peter Palenchar (Dept. of Chemistry; Rutgers University-Camden)

Abstract:
tRNA is the most heavily modified tRNA in terms of the percentage of bases and has the most chemical diversity. The function of some of these modifications is still unknown. It has been suggested that some of them might play a role as sensors of enviromental stressors, but only this has only been demonstrated to be true for 4-thiouridine, which is a sensor for Near-UV light. There are links between oxidative stress responses and Near-UV light responses. To investigate the role of tRNA modifications, such as 4-thiouridine, in oxidative stress response, we have determined the levels of the tRNA modified bases at different time points and two different methods of inducing oxidative stress in E. coli
We find that hydrogen peroxide, a strong oxidant, and diamide, only a thiol oxidant, both cause changes in the tRNA modification patterns, that these patterns are unique, and that changes in the levels of the tRNA modifications occur only after 5 minutes of exposure and before any detectable growth defects. Analysis of mutants defecient in some tRNA modifications show different patterns than wild-type when exposed to oxidative stress.

Keywords: tRNA modification, oxidative stress