Figure 6.

Novel TA systems predicted by deep sequencing analysis. (A) Genomic locus of three new TA systems in B. subtilis. The toxic protein (gray arrow) and the RNA antitoxin (black arrow) are all arranged in tail-to-tail configuration. Note that the txpA and ratA system had been previously characterized (46). (B) Northern blotting of the toxin and antitoxin RNAs. ‘Asterisk’ indicates that the size of the sRNA as predicted by northern blot is in agreement with sequencing data. ‘Filled triangle’ denotes sRNA with different predicted size (e.g. due to processing or termination events). The expression level for bsrH and as-bsrH were too low to be detected by northern blotting in our analysis. (C) Putative sequences for as-bsrE, bsrG and bsrH toxins. Predicted membrane spanning regions are highlighted in gray. (D) Sequence alignment of the bsrE, as-bsrG and as-bsrH RNA antitoxins. Regions with base-pairing potentials are shown with different colors and labeled as P1–P4.