title: Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection.
abstract: We have systematically made a set of precisely defined, single-gene deletions of all nonessential genes in Escherichia coli K-12. Open-reading frame coding regions were replaced with a kanamycin cassette flanked by FLP recognition target sites by using a one-step method for inactivation of chromosomal genes and primers designed to create in-frame deletions upon excision of the resistance cassette. Of 4288 genes targeted, mutants were obtained for 3985. To alleviate problems encountered in high-throughput studies, two independent mutants were saved for every deleted gene. These mutants-the 'Keio collection'-provide a new resource not only for systematic analyses of unknown gene functions and gene regulatory networks but also for genome-wide testing of mutational effects in a common strain background, E. coli K-12 BW25113. We were unable to disrupt 303 genes, including 37 of unknown function, which are candidates for essential genes. Distribution is being handled via GenoBase (http://ecoli.aist-nara.ac.jp/).
authors.affiliation: Institute for Advanced Biosciences, Keio University, Tsuruoka City, Yamagata, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Baba
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ara
authors.forename: Miki
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Yuki
authors.initials: Y
authors.lastname: Takai
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Okumura
authors.forename: Miki
authors.initials: M
authors.lastname: Baba
authors.forename: Kirill A
authors.initials: KA
authors.lastname: Datsenko
authors.forename: Masaru
authors.initials: M
authors.lastname: Tomita
authors.forename: Barry L
authors.initials: BL
authors.lastname: Wanner
authors.forename: Hirotada
authors.initials: H
authors.lastname: Mori
mesh_terms: D004926:Escherichia coli / Q000235:genetics*; D017353:Gene Deletion; D020407:Internet; D009154:Mutation; D030781:Organisms, Genetically Modified