IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
artículos
Título:
Balance between bacterial extracellular matrix production and intramacrophage proliferation by a Salmonella-specific SPI-2-encoded transcription factor
Autor/es:
FIGUEROA, NICOLÁS R.; GARCÍA?DEL PORTILLO, FRANCISCO; ECHARREN, MARÍA LAURA; PUCCIARELLI, M. GRACIELA; VITOR-HOREN, LUISINA; SONCINI, FERNANDO C.
Revista:
MOLECULAR MICROBIOLOGY
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Año: 2021 vol. 116 p. 1022 - 1032
ISSN:
0950-382X
Resumen:
Biosynthesis and secretion of a complex extracellular matrix (EM) is a hallmark of Salmonella biofilm formation, impacting on its relationship with both the environment and the host. Cellulose is a major component of Salmonella EM. It is considered an anti-virulence factor because it interferes with Salmonella proliferation inside macrophages and virulence in mice. Its synthesis is stimulated by CsgD, the master regulator of biofilm formation in enterobacteria, which in turn is under the control of MlrA, a MerR-like transcription factor. In this work, we identified a SPI-2-encoded Salmonella-specific transcription factor homolog to MlrA, MlrB, that represses transcription of its downstream gene, orf319, and of csgD inside host cells. MlrB is induced in laboratory media mimicking intracellular conditions and inside macrophages, and it is required for intramacrophage proliferation. An increased csgD expression is observed in the absence of MlrB inside host cells. Interestingly, inactivation of the CsgD-controlled cellulose synthase-coding gene restored intramacrophage proliferation to rates comparable to wild-type bacteria in the absence of MlrB. These data indicate that MlrB represses CsgD expression inside host cells and suggest that this repression lowers the activation of the cellulose synthase. Our findings provide a novel link between biofilm formation and Salmonella virulence.