Expression of canonical SOS genes is not under LexA repression in Bdellovibrio bacteriovorus
Campoy Sánchez, Susana (Institut de Recerca i Tecnologia Agroalimentàries. Centre de Recerca en Sanitat Animal)
Salvador, Noelia (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
Cortés Garmendia, M. Pilar (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
Erill, Ivan (Centro Nacional de Microelectrónica (Espanya))
Barbé García, Jordi (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)

Date:	2005
Abstract:	The here-reported identification of the LexA-binding sequence of Bdellovibrio bacteriovorus, a bacterial predator belonging to the delta-Proteobacteria, has made possible a detailed study of its LexA regulatory network. Surprisingly, only the lexA gene and a multiple gene cassette including dinP and dnaE homologues are regulated by the LexA protein in this bacterium. In vivo expression analyses have confirmed that this gene cassette indeed forms a polycistronic unit that, like the lexA gene, is DNA damage inducible in B. bacteriovorus. Conversely, genes such as recA, uvrA, ruvCAB, and ssb, which constitute the canonical core of the Proteobacteria SOS system, are not repressed by the LexA protein in this organism, hinting at a persistent selective pressure to maintain both the lexA gene and its regulation on the reported multiple gene cassette. In turn, in vitro experiments show that the B. bacteriovorus LexA-binding sequence is not recognized by other delta-Proteobacteria LexA proteins but binds to the cyanobacterial LexA repressor. This places B. bacteriovorus LexA at the base of the delta-Proteobacteria LexA family, revealing a high degree of conservation in the LexA regulatory sequence prior to the diversification and specialization seen in deeper groups of the Proteobacteria phylum.
Grants:	Ministerio de Educación y Ciencia BFM2004-02768/BMC Agència de Gestió d'Ajuts Universitaris i de Recerca 2001/SGR-206
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Published in:	Journal of bacteriology, Vol. 187, issue 15 (Aug. 2005) , p. 5367-5375, ISSN 0021-9193

DOI: 10.1128/JB.187.15.5367-5375.2005
PMID: 16030231

Postprint 30 p, 501.4 KB

The record appears in these collections:
Articles > Research articles
Articles > Published articles