Back to Search
Start Over
The nucleoid protein HU positively regulates the expression of type VI secretion systems in Enterobacter cloacae .
- Source :
-
MSphere [mSphere] 2024 May 29; Vol. 9 (5), pp. e0006024. Date of Electronic Publication: 2024 Apr 22. - Publication Year :
- 2024
-
Abstract
- Enterobacter cloacae is an emerging pathogen isolated in healthcare-associated infections. A major virulence factor of this bacterium is the type VI secretion system (T6SS). The genome of E. cloacae harbors two T6SS gene clusters (T6SS-1 and T6SS-2), and the functional characterization of both systems showed that these two T6SSs are not expressed under the same conditions. Here, we report that the major histone-like protein HU positively regulates the expression of both T6SSs and, therefore, the function that each T6SS exerts in E. cloacae . Single deletions of the genes encoding the HU subunits ( hupA and hupB ) decreased mRNA levels of both T6SS. In contrast, the hupA hupB double mutant dramatically affected the T6SS expression, diminishing its transcription. The direct binding of HU to the promoter regions of T6SS-1 and T6SS-2 was confirmed by electrophoretic mobility shift assay. In addition, single and double mutations in the hup genes affected the ability of inter-bacterial killing, biofilm formation, adherence to epithelial cells, and intestinal colonization, but these phenotypes were restored when such mutants were trans -complemented. Our data broaden our understanding of the regulation of HU-mediated T6SS in these pathogenic bacteria.<br />Importance: T6SS is a nanomachine that functions as a weapon of bacterial destruction crucial for successful colonization in a specific niche. Enterobacter cloacae expresses two T6SSs required for bacterial competition, adherence, biofilm formation, and intestinal colonization. Expression of T6SS genes in pathogenic bacteria is controlled by multiple regulatory systems, including two-component systems, global regulators, and nucleoid proteins. Here, we reported that the HU nucleoid protein directly activates both T6SSs in E. cloacae , affecting the T6SS-related phenotypes. Our data describe HU as a new regulator involved in the transcriptional regulation of T6SS and its impact on E. cloacae pathogenesis.<br />Competing Interests: The authors declare no conflict of interest.
- Subjects :
- Promoter Regions, Genetic
Multigene Family
Enterobacter cloacae genetics
Enterobacter cloacae metabolism
Gene Expression Regulation, Bacterial
Bacterial Proteins genetics
Bacterial Proteins metabolism
Type VI Secretion Systems genetics
Type VI Secretion Systems metabolism
DNA-Binding Proteins genetics
DNA-Binding Proteins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 2379-5042
- Volume :
- 9
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- MSphere
- Publication Type :
- Academic Journal
- Accession number :
- 38647313
- Full Text :
- https://doi.org/10.1128/msphere.00060-24