Construction and characterization of mutations in hupB, the gene encoding HU-beta (HU-1) in Escherichia coli K-12.
Plasmid pJMC21 contains Escherichia coli chromosomal DNA encoding Lon protease, HU-beta (HU-1), and an unidentified 67,000-dalton protein. A kanamycin resistance cassette was used in the construction of insertion and deletion mutations in hupB, the gene encoding HU-beta on plasmid pJMC21. The reconstructed plasmids were linearized and used to introduce hupB chromosomal mutations into JC7623 (recBC sbcBC). These mutations, as expected, mapped in the 9.8-min region of the E. coli chromosome by P1 transduction (16% linkage to proC+). Southern blot hybridization of chromosomal fragments verified that hupB+ was replaced by the mutant allele, with no indication of gene duplication. All the mutant strains had growth rates identical to that of wild-type E. coli, were resistant to UV irradiation and nitrofurantoin, and supported the in vivo transposition-replication of bacteriophage Mu, Mu lysogenization, Tn10 transposition from lambda 1098, and lambda replication-lysogenization. The only observable phenotypic variation was a reduced Mu plaque size on the hupB mutant strains; however, the yield of bacteriophage Mu in liquid lysates prepared from the mutant strains was indistinguishable from the yield for the wild type.
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Department of Biochemistry and Molecular Biology, University of Chicago, Illinois 60637.
Markovitz
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D049069:ATP-Dependent Proteases; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D006360:Heat-Shock Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D009693:Nucleic Acid Hybridization; D010641:Phenotype; D010957:Plasmids; D049070:Protease La; D012689:Sequence Homology, Nucleic Acid; D012697:Serine Endopeptidases / Q000235:genetics; D014161:Transduction, Genetic
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; C040330:histone-like protein HU, bacteria; D049069:ATP-Dependent Proteases; D012697:Serine Endopeptidases; C483567:Lon protein, E coli; D049070:Protease La