| Autor: |
Cao, Thanh Nguyen, Joyet, Philippe, Aké, Francine Moussan Désirée, Milohanic, Eliane, Deutscher, Josef |
| Zdroj: |
Journal of Molecular Microbiology and Biotechnology; July 2020, Vol. 29 Issue: 1-6 p10-26, 17p |
| Abstrakt: |
Background:Many bacteria transport cellobiose via a phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS). In Listeria monocytogenes, two pairs of soluble PTS components (EIIACel1/EIIBCel1 and EIIACel2/EIIBCel2) and the permease EIICCel1 were suggested to contribute to cellobiose uptake. Interestingly, utilization of several carbohydrates, including cellobiose, strongly represses virulence gene expression by inhibiting PrfA, the virulence gene activator. Results:The LevR-like transcription regulator CelR activates expression of the cellobiose-induced PTS operons celB1-celC1-celA1, celB2-celA2, and the EIIC-encoding monocistronic celC2. Phosphorylation by P∼His-HPr at His550 activates CelR, whereas phosphorylation by P∼EIIBCel1 or P∼EIIBCel2 at His823 inhibits it. Replacement of His823 with Ala or deletion of both celAor celBgenes caused constitutive CelR regulon expression. Mutants lacking EIICCel1, CelR or both EIIACel exhibitedslow cellobiose consumption. Deletion of celC1or celRprevented virulence gene repression by the disaccharide, but not by glucose and fructose. Surprisingly, deletion of both celAgenes caused virulence gene repression even during growth on non-repressing carbohydrates. No cellobiose-related phenotype was found for the celC2mutant. Conclusion:The two EIIA/BCel pairs are similarly efficient as phosphoryl donors in EIICCel1-catalyzed cellobiose transport and CelR regulation. The permanent virulence gene repression in the celAdouble mutant further supports a role of PTSCel components in PrfA regulation. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
