A Genome-Wide View of theEscherichia coliBasS–BasR Two-component System Implicated in Iron-responses

Novel regulation targets of the metal-response BasS–BasR two-component system of Escherichia coli

“…2, Tables 1 and 2). Genomewide transcriptome analysis of a E. coli basS mutant (Hagiwara et al, 2004) and of wild-type E. coli in the presence of excess Zn(II) (Lee et al, 2005) indicates that the arnBCADTEF operon is under the control of the Using the consensus BasR-binding sequence identified by DNase footprint analysis (see Fig. 4d) as a probe, the locations of BasRbinding sites were searched for within the major target promoters identified by SELEX-chip (see Fig.…”

“…BasSR TCS (Hagiwara et al, 2004;Lee et al, 2005). An E. coli mutant carrying a constitutive basR gene expresses constitutively the genes for membrane modification, such as the arnB and eptA operons, in the presence of Fe and Zn (Froelich et al, 2006).…”

“…Genome-wide transcriptome analysis indicated that BasSRdependent gene products are involved in survival under acid and/or anaerobic conditions (Hagiwara et al, 2004;Lee et al, 2005). Here we found that some genes encoding enzymes for energy metabolism under acid-and/or anaerobic conditions were under the direct control of BasSR (see Tables 1 and 2): (1) both aceF and aceE are members of the pyruvate dehydrogenase operon, which is involved in acetate metabolism (Quail et al, 1994); (2) the hyaA and hyaB genes encode the small and large subunits of hydrogenase 1, respectively (Menon et al, 1991); and (3) the cydAB operon encodes cytochrome bd-I terminal oxidase (Green et al, 1984), which is expressed under oxygen-limited conditions and needed for growth under anaerobic conditions (Cotter et al, 1990).…”

“…In addition, BasSR is involved in the response to toxic iron, as first indicated by Salmonella PrmAB. BasSR-dependent expression of the arnBCADTEF operon has been found to increase during growth with elevated Fe(II) or Fe(III) (Hagiwara et al, 2004;Lee et al, 2005). Deletion of basSR results in acid sensitivity during growth at elevated iron concentrations (Hagiwara et al, 2004).…”

“…The assimilation of essential elements (K, P, N and Mg) is under the control of the KdpDE (Asha & Gowrishankar, 1993), PhoRB (Wanner & Chang, 1987), GlnLG (or NtrBC) (Ninfa & Magasanik, 1986) and PhoQP (Kato et al, 1999) TCS pairs, respectively, while BasSR (Fe, Zn), CusSR (Cu), CpxAR (Cu) and ZraSR (Zn) TCSs are involved in the E. coli response to essential but toxic divalent metals (Yamamoto et al, 2005;Yamamoto & Ishihama, 2005a, b, 2006. Microarray analysis indicated that the E. coli BasSR system controls, directly or indirectly, a set of genes that are associated with metal-response membrane modification, and genes for response to acidic and/or anaerobic growth conditions (Hagiwara et al, 2004;Lee et al, 2005). The whole set of target promoters under the direct control of BasSR remains unidentified, however.…”