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Author (up) Gregg-Jolly, L.A.; Ornston, L.N. file  url
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  Title Properties of Acinetobacter calcoaceticus recA and its contribution to intracellular gene conversion Type Journal Article
  Year 1994 Publication Molecular Microbiology Abbreviated Journal Mol Microbiol  
  Volume 12 Issue 6 Pages 985-992  
  Keywords Acinetobacter calcoaceticus/*genetics/metabolism; Amino Acid Sequence; *Bacterial Proteins; Base Sequence; Cloning, Molecular; DNA Transposable Elements; *DNA-Binding Proteins; Escherichia coli/genetics; Gene Conversion/*physiology; Genes, Bacterial/*genetics; Genetic Complementation Test; Genomic Library; Molecular Sequence Data; Mutation/physiology; Rec A Recombinases/chemistry/*genetics/metabolism; Restriction Mapping; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Transformation, Bacterial  
  Abstract The Acinetobacter calcoaceticus pcaJ and catJ genes, nearly identical in DNA sequence, differ in transcriptional control and are separated by more than 20 kb of chromosomal DNA. The pcaJ3125 mutation is repaired frequently in organisms containing the wild-type catJ gene. This high-frequency repair is eliminated in strains lacking the catJ gene, which suggests that recombination between the homologous catJ and pcaJ genes contributes to the high-frequency repair of the pcaJ3125 mutation. We report here that the high-frequency repair also requires a functional recA gene. The A. calcoaceticus recA gene was cloned in Escherichia coli by complementation of a recA mutation in the host strain. The nucleotide sequence of a 1506 bp DNA fragment containing A. calcoaceticus recA was determined. The amino acid sequences of RecA from E. coli and A. calcoaceticus shared 71% identity. The DNA sequences differed in that a consensus binding site for binding of LexA repressor, represented upstream from recA in E. coli, is not evident in the corresponding region of the A. calcoaceticus DNA sequence. A Tn5 insertion was introduced into the A. calcoaceticus recA gene. Selection for Tn5-encoded kanamycin resistance allowed the inactivated recA gene to be recombined by natural transformation into the A. calcoaceticus chromosome. Strains that had acquired the mutant gene were sensitive to both MMS and u.v. light, were deficient in natural transformation, and failed to carry out catJ-dependent high-frequency repair of the pcaJ3125 mutation.  
  Call Number Serial 299  
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Author (up) Shanks, R.M.Q.; Lahr, R.M.; Stella, N.A.; Arena, K.E.; Brothers, K.M.; Kwak, D.H.; Liu, X.; Kalivoda, E.J. file  url
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  Title A Serratia marcescens PigP homolog controls prodigiosin biosynthesis, swarming motility and hemolysis and is regulated by cAMP-CRP and HexS Type Journal Article
  Year 2013 Publication PloS one Abbreviated Journal PLoS One  
  Volume 8 Issue 3 Pages e57634  
  Keywords Bacterial Proteins/*genetics/metabolism; Depsipeptides/*biosynthesis/genetics/pharmacology; Erythrocytes/drug effects; *Gene Expression Regulation, Bacterial; Genetic Complementation Test; Hemolysis/drug effects; Hexosyltransferases/genetics/metabolism; Humans; Membrane Proteins/genetics/metabolism; Movement/drug effects; Mutation; Operon; Prodigiosin/*biosynthesis; Sequence Homology, Amino Acid; Serratia marcescens/*genetics/metabolism; Signal Transduction; Transcription Factors/*genetics/metabolism  
  Abstract Swarming motility and hemolysis are virulence-associated determinants for a wide array of pathogenic bacteria. The broad host-range opportunistic pathogen Serratia marcescens produces serratamolide, a small cyclic amino-lipid, that promotes swarming motility and hemolysis. Serratamolide is negatively regulated by the transcription factors HexS and CRP. Positive regulators of serratamolide production are unknown. Similar to serratamolide, the antibiotic pigment, prodigiosin, is regulated by temperature, growth phase, HexS, and CRP. Because of this co-regulation, we tested the hypothesis that a homolog of the PigP transcription factor of the atypical Serratia species ATCC 39006, which positively regulates prodigiosin biosynthesis, is also a positive regulator of serratamolide production in S. marcescens. Mutation of pigP in clinical, environmental, and laboratory strains of S. marcescens conferred pleiotropic phenotypes including the loss of swarming motility, hemolysis, and severely reduced prodigiosin and serratamolide synthesis. Transcriptional analysis and electrophoretic mobility shift assays place PigP in a regulatory pathway with upstream regulators CRP and HexS. The data from this study identifies a positive regulator of serratamolide production, describes novel roles for the PigP transcription factor, shows for the first time that PigP directly regulates the pigment biosynthetic operon, and identifies upstream regulators of pigP. This study suggests that PigP is important for the ability of S. marcescens to compete in the environment.  
  Call Number Serial 1612  
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