Identification of phosphate starvation-inducible genes in Escherichia coli K-12 by DNA sequence analysis of psi::lacZ(Mu d1) transcriptional fusions.
Twenty-four independent phosphate starvation-inducible (psi) transcriptional fusions made with Mu d1(lacZbla) were analyzed by sequencing the psi::lacZ(Mu d1) chromosomal junctions by using DNAs amplified with the polymerase chain reaction or mini-Mu cloning. Our DNA sequence analysis showed that the MuR DNA in Mu d1 has an unexpected structure that is comprised of 104 bases of MuR DNA in the form of a large inverted repeat, which we denoted Mu d1-R. Also, Mu d1s in the phoA and phn (psiD) loci of the phosphate regulon showed regional specificities for the insertion sites despite the randomness of Mu d1 insertions into the genome as a whole. Gene products or open reading frames were identified for seven unknown psi::lacZ(Mu d1) transcriptional fusions by searching DNA data bases with the sequences adjacent and upstream of the Mu d1s. One psiC::lacZ(Mu d1) lies in the ugpB gene of the ugpBAEC operon, which encodes a periplasmic sn-glycerol-3-phosphate-binding protein; two psiQ::lacZ(Mu d1)s lie in the gltB gene, and one psiQ::lacZ(Mu d1) lies in the gltD gene of the gltBDF operon, encoding the large and small subunits of glutamate synthase, respectively; and the psi-51::lacZ(Mu d1) lies in the glpB gene of the glpABC operon, which codes for the anaerobically regulated glycerol-3-phosphate dehydrogenase. psiE and psiF::lacZ(Mu d1)s lie in uncharacterized open reading frames near the xylE and phoA genes, respectively. Six other psi::lacZ(Mu d1)s lie in yet unreported Escherichia coli sequences.
Metcalf
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Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907.
Steed
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Wanner
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D010583:Bacteriophage mu / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000032:analysis*; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D007763:Lac Operon; D008969:Molecular Sequence Data; D009876:Operon; D010710:Phosphates / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D010710:Phosphates