title: HU participates in expression of a specific set of genes required for growth and survival at acidic pH in Escherichia coli.
abstract: The major histone-like Escherichia coli protein, HU, is composed of alpha and beta subunits respectively encoded by hupA and hupB in Escherichia coli. A mutant deficient in both hupA and hupB grew at a slightly slower rate than the wild type at pH 7.5. Growth of the mutant diminished with a decrease in pH, and no growth was observed at pH 4.6. Mutants of either hupA or hupB grew at all pH levels tested. The arginine-dependent survival at pH 2.5 was diminished approximately 60-fold by the deletion of both hupA and hupB, whereas the survival was slightly affected by the deletion of either hupA or hupB. The mRNA levels of adiA and adiC, which respectively encode arginine decarboxylase and arginine/agmatine antiporter, were low in the mutant deficient in both hupA and hupB. The deletion of both hupA and hupB had little effect on survival at pH 2.5 in the presence of glutamate or lysine, and expression of the genes for glutamate and lysine decarboxylases was not impaired by the deletion of the HU genes. These results suggest that HU regulates expression of the specific set of genes required for growth and survival in acidic environments.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
authors.forename: Hongkai
authors.initials: H
authors.lastname: Bi
authors.forename: Lianle
authors.initials: L
authors.lastname: Sun
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Fukamachi
authors.forename: Hiromi
authors.initials: H
authors.lastname: Saito
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kobayashi
mesh_terms: D000143:Acids / Q000494:pharmacology*; D026905:Amino Acid Transport Systems / Q000096:biosynthesis; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017920:Antiporters / Q000096:biosynthesis; D002262:Carboxy-Lyases / Q000096:biosynthesis; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000187:drug effects / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D018698:Glutamic Acid / Q000378:metabolism; D008239:Lysine / Q000378:metabolism; D050296:Microbial Viability; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*
chemical_list: D000143:Acids; C476528:AdiC protein, E coli; D026905:Amino Acid Transport Systems; D000900:Anti-Bacterial Agents; D017920:Antiporters; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C541388:HupB protein, E coli; D014157:Transcription Factors; C490937:hupA protein, E coli; D018698:Glutamic Acid; D002262:Carboxy-Lyases; C019722:arginine decarboxylase; D008239:Lysine