Poster abstracts

Poster number 37 submitted by Kathryn Kirschner

Effect of dark and/or light conditions on nucleoside modifications in total tRNA of Cucumis sativus

Kathryn Kirschner (Chemistry Department, University of Cincinnati), Balasubrahmanyam Addepalli (Chemistry Department, University of Cincinnati), Patrick Limbach (Chemistry Department, University of Cincinnati)

Abstract:
Nucleoside modifications are a universal feature of transfer RNA, but their levels are influenced by various factors such as light exposure, dark, temperature, water stress, etc. In this report, we present data that suggests differential modification levels in total tRNA isolated from Cucumis sativus cotyledons grown under either 12 hr dark and 12 hr light conditions, total dark or dark grown but exposed to light 24 hr before harvesting. Comparative nucleoside analysis of total tRNA isolated from these plant samples revealed interesting features. While all the plant samples exhibited nucleoside modifications such as pseudouridine, 2’-O-methyluridine, 1-methylguanosine or 2’-O-methylguanosine, and 2’-O-ribosyladenosine, completely dark grown plants exhibited elevated levels of 1-methyladenosine, N4-acetylcytidine or N2–methylguanosine. On the other hand, plants grown under 12 hr dark and 12 hr light conditions as well as the dark grown but exposed to 24 hr light exhibited higher levels of 2’-O-methylcytidine. The dark grown exposed to light also exhibited higher levels of N4-acetylcytidine or N2–methylguanosine. Several peaks were unidentifiable in the respective chromatograms in all the plant samples. Further analysis involves collecting fractions and subsequent analysis by mass spectrometry to determine the identity of these modifications. The implications associated with increased levels of nucleoside modifications in response to extreme environmental conditions will be discussed.

References:
Jayabaskaran C. and Hande S. Plant Growth Regulation 1995, 16: 73-81.

Pomerantz S.C. and McCloskey J. 1993, 193, 796-824.

Keywords: Nucleoside modifications, tRNA, Cucumis sativus