Sigma factor-anti-sigma factor interaction in alginate synthesis: inhibition of AlgT by MucA.
AUTOR(ES)
Xie, Z D
RESUMO
Conversion from the nonmucoid to the mucoid phenotype is a typical feature of Pseudomonas aeruginosa strains causing chronic pulmonary infections in cystic fibrosis patients. One of the key genetic controls in this conversion to mucoidy is from the algT(U)-mucA-mucB(algN) locus, located at 67.5 min on the standard P. aeruginosa chromosomal map. The algT gene promotes conversion to mucoidy and encodes an alternative sigma factor (sigma E) which belongs to the ECF (for extracytoplasmic function) family. On the other hand, the mucA and mucB (algN) genes suppress conversion to mucoidy. Loss-of-function mutations in mucA have been postulated to be the cause of mucoidy in some P. aeruginosa strains isolated from cystic fibrosis patients. We expressed and purified the protein products from the mucA and mucB open reading frames. The purified MucA protein abolishes the in vitro transcription specified by AlgT and the ability of AlgT to compete with an Escherichia coli sigma factor, FliA, suggesting that inhibiting AlgT-dependent transcription could be the mechanism by which mucA suppresses mucoidy in vivo. Enzyme-linked immunosorbent assay and glycerol density gradient sedimentation experiments suggest that MucA physically interacts with AlgT.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=178284Documentos Relacionados
- Posttranslational control of the algT (algU)-encoded sigma22 for expression of the alginate regulon in Pseudomonas aeruginosa and localization of its antagonist proteins MucA and MucB (AlgN).
- The algT (algU) gene of Pseudomonas aeruginosa, a key regulator involved in alginate biosynthesis, encodes an alternative sigma factor (sigma E).
- Negative Control of Flagellum Synthesis in Pseudomonas aeruginosa Is Modulated by the Alternative Sigma Factor AlgT (AlgU)
- Control of Pseudomonas aeruginosa algZ Expression by the Alternative Sigma Factor AlgT
- A mutation in algN permits trans activation of alginate production by algT in Pseudomonas species.
