title: Single-stranded DNA catenation mediated by human EVL and a type I topoisomerase.
abstract: The human Ena/Vasp-like (EVL) protein is considered to be a bifunctional protein, involved in both actin remodeling and homologous recombination. In the present study, we found that human EVL forms heat-stable multimers of circular single-stranded DNA (ssDNA) molecules in the presence of a type I topoisomerase in vitro. An electron microscopic analysis revealed that the heat-stable ssDNA multimers formed by EVL and topoisomerase were ssDNA catemers. The ssDNA catenation did not occur when either EVL or topoisomerase was omitted from the reaction mixture. A deletion analysis revealed that the ssDNA catenation completely depended on the annealing activity of EVL. Human EVL was captured from a human cell extract by TOPO IIIα-conjugated beads, and the interaction between EVL and TOPO IIIα was confirmed by a surface plasmon resonance analysis. Purified TOPO IIIα catalyzed the ssDNA catenation with EVL as efficiently as the Escherichia coli topoisomerase I. Since the ssDNA cutting and rejoining reactions, which are the sub-steps of ssDNA catenation, may be an essential process in homologous recombination, EVL and TOPO IIIα may function in the processing of DNA intermediates formed during homologous recombination.
authors.affiliation: Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
authors.forename: Motoki
authors.initials: M
authors.lastname: Takaku
authors.forename: Daisuke
authors.initials: D
authors.lastname: Takahashi
authors.forename: Shinichi
authors.initials: S
authors.lastname: Machida
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ueno
authors.forename: Noriko
authors.initials: N
authors.lastname: Hosoya
authors.forename: Shukuko
authors.initials: S
authors.lastname: Ikawa
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Miyagawa
authors.forename: Takehiko
authors.initials: T
authors.lastname: Shibata
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kurumizaka
mesh_terms: D015815:Cell Adhesion Molecules / Q000378:metabolism*; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D043864:DNA, Catenated / Q000378:metabolism* / Q000648:ultrastructure; D004277:DNA, Single-Stranded / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D008954:Models, Biological
chemical_list: D015815:Cell Adhesion Molecules; D043864:DNA, Catenated; D004277:DNA, Single-Stranded; C484449:EVL protein, human; D004264:DNA Topoisomerases, Type I