title: Characterization of a novel inhibitory feedback of the anti-anti-sigma SpoIIAA on Spo0A activation during development in Bacillus subtilis.
abstract: Compartmentalized gene expression during sporulation is initiated after asymmetric division by cell-specific activation of the transcription factors sigmaF and sigmaE. Synthesis of these sigma factors, and their regulatory proteins, requires the activation (phosphorylation) of Spo0A by the phosphorelay signalling system. We report here a novel regulatory function of the anti-anti-sigmaF SpoIIAA as inhibitor of Spo0A activation. This effect did not require sigmaF activity, and it was abolished by expression of the phosphorelay-independent form Spo0A-Sad67 indicating that SpoIIAA directly interfered with Spo0A approximately P generation. IPTG-directed synthesis of the SpoIIE phosphatase in a strain carrying a multicopy plasmid coding for SpoIIAA and its specific inhibitory kinase SpoIIAB blocked Spo0A activation suggesting that the active form of the inhibitor was SpoIIAA and not SpoIIAA-P. Furthermore, expression of the non-phosphorylatable mutant SpoIIAAS58A (SpoIIAA-like), but not SpoIIAAS58D (SpoIIAA-P-like), completely blocked Spo0A-dependent gene expression. Importantly, SpoIIAA expressed from the chromosome under the control of its normal spoIIA promoter showed the same negative effect regulated not only by SpoIIAB and SpoIIE but also by septum morphogenesis. These findings are discussed in relation to the potential contribution of this novel inhibitory feedback with the proper activation of sigmaF and sigmaE during development.
authors.affiliation: Department of Microbiology, Rosario University School of Biochemistry and Pharmacy, and Institute for Molecular and Cellular Biology of Rosario, IBR-CONICET. Suipacha 531, Sala 9, Rosario-2000, Argentina.
authors.forename: Ana L
authors.initials: AL
authors.lastname: Arabolaza
authors.forename: Akira
authors.initials: A
authors.lastname: Nakamura
authors.forename: María E
authors.initials: ME
authors.lastname: Pedrido
authors.forename: Luciano
authors.initials: L
authors.lastname: Martelotto
authors.forename: Lelia
authors.initials: L
authors.lastname: Orsaria
authors.forename: Roberto R
authors.initials: RR
authors.lastname: Grau
mesh_terms: D019943:Amino Acid Substitution; D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D002451:Cell Compartmentation; D025461:Feedback, Physiological; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D017930:Genes, Reporter; D007544:Isopropyl Thiogalactoside / Q000494:pharmacology; D007763:Lac Operon; D008957:Models, Genetic; D020125:Mutation, Missense; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D011499:Protein Processing, Post-Translational; D011993:Recombinant Fusion Proteins / Q000502:physiology; D012808:Sigma Factor / Q000378:metabolism; D013171:Spores, Bacterial; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; C064971:FliA protein, Bacteria; D011993:Recombinant Fusion Proteins; D012808:Sigma Factor; C080950:Spo0A protein, Bacillus subtilis; D014157:Transcription Factors; C030069:spore-specific proteins, Bacillus; C063202:sporulation-specific sigma factors; D007544:Isopropyl Thiogalactoside