title: Initiation of Chromosomal Replication in Predatory BacteriumBdellovibrio bacteriovorus.
abstract: Bdellovibrio bacteriovorusis a small Gram-negative predatory bacterium that attacks other Gram-negative bacteria, including many animal, human, and plant pathogens. This bacterium exhibits a peculiar biphasic life cycle during which two different types of cells are produced: non-replicating highly motile cells (the free-living phase) and replicating cells (the intracellular-growth phase). The process of chromosomal replication inB. bacteriovorusmust therefore be temporally and spatially regulated to ensure that it is coordinated with cell differentiation and cell cycle progression. Recently,B. bacteriovorushas received considerable research interest due to its intriguing life cycle and great potential as a prospective antimicrobial agent. Although, we know that chromosomal replication in bacteria is mainly regulated at the initiation step, no data exists about this process inB. bacteriovorus. We report the first characterization of key elements of initiation of chromosomal replication - DnaA protein andoriCregion from the predatory bacterium,B. bacteriovorus.In vitrostudies using different approaches demonstrate that theB. bacteriovorus oriC(BdoriC) is specifically bound and unwound by the DnaA protein. Sequence comparison of the DnaA-binding sites enabled us to propose a consensus sequence for theB. bacteriovorusDnaA box [5'-NN(A/T)TCCACA-3']. Surprisingly,in vitroanalysis revealed that BdoriCis also bound and unwound by the host DnaA proteins (relatively distantly related fromB. bacteriovorus). We compared the architecture of the DnaA-oriCcomplexes (orisomes) in homologous (oriCand DnaA fromB. bacteriovorus) and heterologous (BdoriCand DnaA from prey,Escherichia coliorPseudomonas aeruginosa) systems. This work provides important new entry points toward improving our understanding of the initiation of chromosomal replication in this predatory bacterium.
authors.affiliation: Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy - Polish Academy of Sciences Wrocław, Poland.
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Makowski
authors.affiliation: Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy - Polish Academy of Sciences Wrocław, Poland.
authors.forename: Rafał
authors.initials: R
authors.lastname: Donczew
authors.affiliation: HTW, Department of Life Science Engineering Berlin, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Weigel
authors.affiliation: Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy - Polish Academy of Sciences Wrocław, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Zawilak-Pawlik
authors.affiliation: Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy - Polish Academy of SciencesWrocław, Poland; Department of Molecular Microbiology, Faculty of Biotechnology, University of WrocławWrocław, Poland.
authors.forename: Jolanta
authors.initials: J
authors.lastname: Zakrzewska-Czerwińska
keywords: Bdellovibrio bacteriovorus; DnaA; Escherichia coli; Pseudomonas putida; initiation of chromosome replication; oriC