A study of the regulation of aminoacyl tRNA synthetase gene expression in Bacillus by T-box regulatory elements

Abstract

The T-box antitermination mechanism is commonly used for the regulation of aminoacyl tRNA synthetase gene expression in Gram positive bacteria. However, expression of lysyl tRNA synthetases is rarely controlled in this way. Bacillus cereus was found to contain a class I lysK gene which has a putative T-box regulatory element upstream (Ataide, et al, 2005). In this work we characterized the T-box regulatory element of lysK from B. cereus. Our results showed that it is functional and responsive to reduced charging of tRNA LYS. Our analysis of 891 sequenced bacterial genomes had shown that all 6 strains containing T-box regulated lysS/K gene also encoded another lysS/K gene in the genome. Work in B. cereus had previously shown that the T-box regulated lysK gene is expressed predominantly in stationary phase and does not charge tRNA LYS during exponential growth (Ataide, et al., 2005). This led us to investigate if a strain of B. subtilis, containing a single lysS/K gene, whose expression is controlled by a T-box mechanism was viable.