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Title: ppGpp, the general stress response alarmone, is required for the expression of the alpha-hemolysin toxin in the uropathogenic EScherichia coli isolate, J96.
Author: Fernández Vázquez, Jorge
Cabrer Panes, Juan David
Aberg, Anna
Juárez Giménez, Antonio
Madrid Xufré, Cristina
Gaviria Cantin, Tania
Fernández Coll, Llorenç
Vargas Sinisterra, Andrés Felipe
Jiménez Moreno, Carlos
Balsalobre Parra, Carlos
Keywords: Regulació genètica
Cèl·lules epitelials
Genetic regulation
Epithelial cells
Issue Date: 14-Oct-2022
Publisher: MDPI
Abstract: ppGpp is an intracellular sensor that, in response to different types of stress, coordinates the rearrangement of the gene expression pattern of bacteria to promote adaptation and survival to new environmental conditions. First described to modulate metabolic adaptive responses, ppGpp modulates the expression of genes belonging to very diverse functional categories. In Escherichia coli, ppGpp regulates the expression of cellular factors that are important during urinary tract infections. Here, we characterize the role of this alarmone in the regulation of the hlyCABDII operon of the UPEC isolate J96, encoding the toxin α-hemolysin that induces cytotoxicity during infection of bladder epithelial cells. ppGpp is required for the expression of the α-hemolysin encoded in hlyCABDII by stimulating its transcriptional expression. Prototrophy suppressor mutations in a ppGpp-deficient strain restore the α-hemolysin expression from this operon to wild-type levels, confirming the requirement of ppGpp for its expression. ppGpp stimulates hlyCABDII expression independently of RpoS, RfaH, Zur, and H-NS. The expression of hlyCABDII is promoted at 37 °C and at low osmolarity. ppGpp is required for the thermoregulation but not for the osmoregulation of the hlyCABDII operon. Studies in both commensal and UPEC isolates demonstrate that no UPEC specific factor is strictly required for the ppGpp-mediated regulation described. Our data further support the role of ppGpp participating in the coordinated regulation of the expression of bacterial factors required during infection.
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It is part of: International Journal of Molecular Sciences, 2022, vol. 23, num. 20
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ISSN: 1422-0067
Appears in Collections:Articles publicats en revistes (Institut de Bioenginyeria de Catalunya (IBEC))
Articles publicats en revistes (Genètica, Microbiologia i Estadística)

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