TY - JOUR
T1 - Identification of a new iron regulated locus of Salmonella typhi
AU - Bäumler, Andreas J.
AU - Tsolis, Renée M.
AU - Van Der Velden, Adrianus W.M.
AU - Stojiljkovic, Igor
AU - Anic, Suzana
AU - Heffron, Fred
N1 - Funding Information:
We thank K.E. Sanderson for sharing unpublished results, B. Ahmer for comments on the manuscript, S. Libby for providing plasmids, K. Poole for helpful discussion, and K. Hantke for experimental advice and for providing bacterial strains. This work was supported by U.S. Public Health Service grant AI 22933 to F.H. from the National Institutes of Health.
PY - 1996
Y1 - 1996
N2 - In order to identify genes belonging to the Fur regulon of Salmonella typhi which are absent from Escherichia coli K-12, a plasmid gene bank consisting of 4000 independent clones was screened for Fur regulated promoters using the Fur titration assay (FURTA). DNA probes generated from FURTA positive plasmids were then used for hybridization with chromosomal DNA from S. typhi, Salmonella typhimurium and E. coli. Using these techniques we identified an iron regulated locus present in S. typhi and S. typhimurium but not in E. coli. Further cloning and nucleotide sequence analysis identified two open reading frames, termed iroBC, organized in a typical operon structure. The genes iroBC were located at 4 and 57 centisomes on the physical maps of Salmonella typhi and S. typhimurium, respectively. This region of the S. typhimurium chromosome contains a large DNA loop which is absent from the corresponding area of the E. coli chromosome. Finally, we developed a new method for generation of single copy transcriptional fusions. A suicide vector was constructed, which allows for the generation of chromosomal fusions to the promoterless E. coli lacZYA genes. By integration of this construct at the iro locus we could establish iron responsive expression of iroBC.
AB - In order to identify genes belonging to the Fur regulon of Salmonella typhi which are absent from Escherichia coli K-12, a plasmid gene bank consisting of 4000 independent clones was screened for Fur regulated promoters using the Fur titration assay (FURTA). DNA probes generated from FURTA positive plasmids were then used for hybridization with chromosomal DNA from S. typhi, Salmonella typhimurium and E. coli. Using these techniques we identified an iron regulated locus present in S. typhi and S. typhimurium but not in E. coli. Further cloning and nucleotide sequence analysis identified two open reading frames, termed iroBC, organized in a typical operon structure. The genes iroBC were located at 4 and 57 centisomes on the physical maps of Salmonella typhi and S. typhimurium, respectively. This region of the S. typhimurium chromosome contains a large DNA loop which is absent from the corresponding area of the E. coli chromosome. Finally, we developed a new method for generation of single copy transcriptional fusions. A suicide vector was constructed, which allows for the generation of chromosomal fusions to the promoterless E. coli lacZYA genes. By integration of this construct at the iro locus we could establish iron responsive expression of iroBC.
KW - Fur regulon
KW - Pulsed field electrophoretic mapping
KW - Salmonella loops
KW - Salmonella typhimurium
KW - Suicide vector
KW - Transcriptional fusion
KW - iro
KW - β-galactosidase
UR - http://www.scopus.com/inward/record.url?scp=0030458858&partnerID=8YFLogxK
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U2 - 10.1016/S0378-1119(96)00560-4
DO - 10.1016/S0378-1119(96)00560-4
M3 - Article
C2 - 8996108
AN - SCOPUS:0030458858
SN - 0378-1119
VL - 183
SP - 207
EP - 213
JO - Gene
JF - Gene
IS - 1-2
ER -