Role of DNA Ligase in the Illegitimate Recombination That Generates bio-Transducing Phages in Escherichia coli

Corresponding author: Hideo Ikeda, Microbial Chemistry, Center for Basic Research, Kitasato Institute, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8642, Japan., ikeda-h{at}kitasato.or.jp (E-mail)

Communicating editor: G. R. SMITH

We studied the role of DNA ligase in illegitimate recombination in Escherichia coli. A temperature-sensitive mutation in the lig gene reduced the frequency with which bio-transducing phages were generated to 10–14% of that of wild type under UV irradiation. Reintroduction of the lig gene into this mutant restored the frequency of recombinant phage generation to that of wild type. Furthermore, overexpression of DNA ligase enhanced illegitimate recombination by 10-fold with or without UV irradiation. In addition, when DNA ligase was present in only limited amounts, UV-induced or spontaneous illegitimate recombination occurred exclusively at hotspot sites that have relatively long sequences of homology (9 or 13 bp). However, when DNA ligase was overexpressed, most of the illegitimate recombination took place at non-hotspot sites having only short sequences of homology (<4 bp). Thus, the level of ligase activity affects the frequency of illegitimate recombination, the length of sequence homology at the recombination sites, and the preference for recombination at hotspots, at least after UV irradiation. These observations support our hypothesis that the illegitimate recombination that generates bio-transducing phages is mediated by the DNA break-and-join mechanism.

This article has been cited by other articles:

				C. Y. Chan, M. Kiechle, P. Manivasakam, and R. H. Schiestl Ionizing radiation and restriction enzymes induce microhomology-mediated illegitimate recombination in Saccharomyces cerevisiae Nucleic Acids Res., August 1, 2007; 35(15): 5051 - 5059. [Abstract] [Full Text] [PDF]

				K. Shiraishi, Y. Imai, S. Yoshizaki, and H. Ikeda Rep helicase suppresses short-homology-dependent illegitimate recombination in Escherichia coli Genes Cells, November 1, 2005; 10(11): 1015 - 1023. [Abstract] [Full Text] [PDF]

				K. Mashimo, M. Kawata, and K. Yamamoto Roles of the RecJ and RecQ proteins in spontaneous formation of deletion mutations in the Escherichia coli K12 endogenous tonB gene Mutagenesis, July 1, 2003; 18(4): 355 - 363. [Abstract] [Full Text] [PDF]

				K. Hanada, T. Yamashita, Y. Shobuike, and H. Ikeda Role of DnaB Helicase in UV-Induced Illegitimate Recombination in Escherichia coli J. Bacteriol., September 1, 2001; 183(17): 4964 - 4969. [Abstract] [Full Text] [PDF]