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Escherichia coli HU protein suppresses DNA‐gyrase‐mediated illegitimate recombination and SOS induction
Author(s) -
Shanado Yuka,
Kato Junichi,
Ikeda Hideo
Publication year - 1998
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1046/j.1365-2443.1998.00208.x
Subject(s) - dna gyrase , dna supercoil , biology , dna , sos response , escherichia coli , homologous recombination , nucleoid , recbcd , microbiology and biotechnology , genetics , site specific recombination , recombination , mutant , circular bacterial chromosome , tn3 transposon , protein–dna interaction , dna replication , recombinase , dna repair , dna binding protein , gene , transposable element , transcription factor
Background The HU protein is an abundant DNA binding protein of bacteria and is a major constituent of the bacterial nucleoid. HU protein is known to be involved in several fundamental biological functions, including DNA supercoiling, DNA replication, site‐specific DNA inversion, and transposition. It is generally thought that a functional relationship exists between HU protein and DNA gyrase. Results We found that an hupA hupB double mutant displays enhanced spontaneous illegitimate recombination during the formation of λ bio transducing phage in Escherichia coli . Nucleotide sequence analysis of the resulting transducing phages showed that the E. coli bio and λ recombination sites did not have any homologous sequence. This mutation also enhanced the spontaneous expression of SOS functions. Furthermore, either overproduced GyrA protein or a temperature‐sensitive gyrB mutation suppressed the illegitimate recombination enhanced by the defect of HU protein. Conclusion These results show that the defect of HU induces illegitimate recombination and SOS response, which are probably mediated by DNA gyrase, implying that HU protein plays roles in suppression of illegitimate recombination and SOS response through interaction with DNA gyrase.