Rationale for the evolutionary retention of two unrelated LYSYL-tRNA synthetases
LysRS1 and LysRS2 are not normally found together within one organism. In the pathogen Bacillus cereus both forms of LysRS are encoded; to investigate what role these two LysRSs might play in B. cereus, their RNA substrate specificities were investigated. It was found that in B. cereus the two different LysRSs together aminoacylate a small RNA of unknown function named tRNAOther. Aminoacylation of tRNAOther was found to be confined to stationary phase, suggesting a role for this non-canonical tRNA in growth phase-specific protein synthesis. Analysis of the non-canonical Watson-Crick base pairs and a bulge in the predicted secondary structure of tRNAOther indicate the importance of these identity elements in recognition by the LysRS1:LysRS2 complex. The role of tRNAOther in B. cereus was also investigated by the construction of a deletion strain, indicating that tRNAOther is not an essential gene. The results implicate tRNAOther in multiple regulatory functions that remain, as yet, uncharacterized.
School:The Ohio State University
School Location:USA - Ohio
Source Type:Master's Thesis
Date of Publication:01/01/2006