Characterization of trigger enzymes involved in the regulation and function of sRNAs in B. subtilis

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So far, only a few so called trigger enzymes are known. These are metabolic enzymes that fulfill a second function in control of gene expression. Trigger enzymes known to date can e.g. bind DNA and act as transcription factors, affect the stability of RNA by binding it, modify proteins by e.g. phosphorylation or inhibit transcription factors by protein/protein interactions. Furthermore, compared to E. coli and other Gram-negative bacteria, not so much is known about sRNAs and their targest in Gram-positive bacteria, in particular B. subtilis. In the latter bacterium, only for five sRNAs targets have been identified, among them for the two sRNAs SR1 and SR4 investigated in our group.In this project we want toa) characterize a novel trigger enzyme, pyruvate carboxylase A (PycA) recently identified in our group as second regulator of the sRNA SR1, in great detail biochemically and concerning its biological role. Both the mechanism of action and the structural and biological prerequisites for its action should be elucidated.b) identify further targets of PycA and analyse the action of this trigger enzymes at the promoters of these target gens.c) demonstrate that glyceraldehyde-3-phosphate-dehydrogenase GapA from B. subtilis is also a trigger enzyme (either a RNase or a protein that interacts with an RNAse or components of the degradosome), whose function is modulated by the small peptide SR1P encoded by SR1d) identify further RNAs whose stability depends on GapA, and investigate the mechanism of action of GapA at these RNAs.