scholarly journals Unique and Universal Features of Epsilonproteobacterial Origins of Chromosome Replication and DnaA-DnaA Box Interactions

2016 ◽  
Vol 7 ◽  
Author(s):  
Pawel Jaworski ◽  
Rafal Donczew ◽  
Thorsten Mielke ◽  
Marcel Thiel ◽  
Stanislaw Oldziej ◽  
...  
Keyword(s):  
Chromosome Replication ◽  
Dnaa Box

scholarly journals Comparative analysis of Caulobacter chromosome replication origins

Microbiology ◽  
2009 ◽  
Vol 155 (4) ◽  
pp. 1215-1225 ◽  
Author(s):  
S. M. Shaheen ◽  
Marie-Claude Ouimet ◽  
Gregory T. Marczynski
Keyword(s):  
Binding Site ◽  
Binding Sites ◽  
Caulobacter Crescentus ◽  
Chromosome Replication ◽  
Integration Host Factor ◽  
Site Directed Mutagenesis ◽  
Replication Origins ◽  
Two Component ◽  
Replication Control ◽  
Dnaa Box

Caulobacter crescentus (CB15) initiates chromosome replication only in stalked cells and not in swarmers. To better understand this dimorphic control of chromosome replication, we isolated replication origins (oris) from freshwater Caulobacter (FWC) and marine Caulobacter (MCS) species. Previous studies implicated integration host factor (IHF) and CcrM DNA methylation sites in replication control. However, ori IHF and CcrM sites identified in the model FWC CB15 were only conserved among closely related FWCs. DnaA boxes and CtrA binding sites are established CB15 ori components. CtrA is a two-component regulator that blocks chromosome replication selectively in CB15 swarmers. DnaA boxes and CtrA sites were found in five FWC and three MCS oris. Usually, a DnaA box and a CtrA site were paired, suggesting that CtrA binding regulates DnaA activity. We tested this hypothesis by site-directed mutagenesis of an MCS10 ori which contains only one CtrA binding site overlapping a critical DnaA box. This overlapping site is unique in the whole MCS10 genome. Selective DnaA box mutations decreased replication, while selective CtrA binding site mutations increased replication of MCS10 ori plasmids. Therefore, both FWC and MCS oris use CtrA to repress replication. Despite this similarity, phylogenetic analysis unexpectedly shows that CtrA usage evolved separately among these Caulobacter oris. We discuss consensus oris and convergent ori evolution in differentiating bacteria.

scholarly journals Putative Cooperative ATP–DnaA Binding to Double-Stranded DnaA Box and Single-Stranded DnaA-Trio Motif upon Helicobacter pylori Replication Initiation Complex Assembly

2021 ◽  
Vol 22 (12) ◽  
pp. 6643
Author(s):  
Pawel Jaworski ◽  
Dorota Zyla-Uklejewicz ◽  
Malgorzata Nowaczyk-Cieszewska ◽  
Rafal Donczew ◽  
Thorsten Mielke ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Replication Initiation ◽  
Dna Unwinding ◽  
Rich Region ◽  
Initiator Protein ◽  
New Class ◽  
H Pylori ◽  
General Architecture ◽  
Dnaa Box

oriC is a region of the bacterial chromosome at which the initiator protein DnaA interacts with specific sequences, leading to DNA unwinding and the initiation of chromosome replication. The general architecture of oriCs is universal; however, the structure of oriC and the mode of orisome assembly differ in distantly related bacteria. In this work, we characterized oriC of Helicobacter pylori, which consists of two DnaA box clusters and a DNA unwinding element (DUE); the latter can be subdivided into a GC-rich region, a DnaA-trio and an AT-rich region. We show that the DnaA-trio submodule is crucial for DNA unwinding, possibly because it enables proper DnaA oligomerization on ssDNA. However, we also observed the reverse effect: DNA unwinding, enabling subsequent DnaA–ssDNA oligomer formation—stabilized DnaA binding to box ts1. This suggests the interplay between DnaA binding to ssDNA and dsDNA upon DNA unwinding. Further investigation of the ts1 DnaA box revealed that this box, together with the newly identified c-ATP DnaA box in oriC1, constitute a new class of ATP–DnaA boxes. Indeed, in vitro ATP–DnaA unwinds H. pylori oriC more efficiently than ADP–DnaA. Our results expand the understanding of H. pylori orisome formation, indicating another regulatory pathway of H. pylori orisome assembly.

CHROMOSOME STRUCTURE IN CHILOCORUS (COLEOPTERA: COCCINELLIDAE). II. THE ASYNCHRONOUS REPLICATION OF CONSTITUTIVE HETEROCHROMATIN

1976 ◽  
Vol 18 (1) ◽  
pp. 85-91 ◽  
Author(s):  
T. J. Ennis
Keyword(s):  
Chromosome Banding ◽  
Chromosome Structure ◽  
Constitutive Heterochromatin ◽  
Chromosome Replication ◽  
Data Models ◽  
Late Replication ◽  
Banding Patterns ◽  
Asynchronous Replication ◽  
Chilocorus Stigma

Chromosome replication has been analysed in four species of Chilocorus. In C. orbus Csy., C. tricyclus Smith, and C. hexacyclus Smith, centric regions of all chromosomes are last to replicate, preceded in order by heterochromatic arms and euchromatic arms. In C. stigma Say, very late replication of centric regions can be detected only in otherwise wholly euchromatic chromosomes (= monophasics); in chromosomes with one arm heterochromatic (= diphasics), these arms are last to replicate. Based on pachytene bivalent morphology and chromosome banding patterns, and supported by autoradiographic data, models are presented for the general organisation of Chilocorus chromosomes. All chromosomes in the first three species are subdivided into euchromatic arm, centric heterochromatin, and either a second euchromatic arm (monophasics) or a heterochromatic arm (diphasics). Chilocorus stigma diphasics apparently lack distinct centric organisation, and are therefore divided into euchromatic and heterochromatic arms only.

A comprehensive set of DnaA‐box mutations in the replication origin, oriC , of Escherichia coli

1996 ◽  
Vol 21 (2) ◽  
pp. 301-311 ◽  
Author(s):  
Uwe Langer ◽  
Stefan Richter ◽  
Angelika Roth ◽  
Christoph Weigel ◽  
Walter Messer
Keyword(s):  
Escherichia Coli ◽  
Replication Origin ◽  
Dnaa Box

scholarly journals Exponential propagation of large circular DNA by reconstitution of a chromosome-replication cycle

2017 ◽  
Vol 45 (20) ◽  
pp. 11525-11534 ◽  
Author(s):  
Masayuki Su’etsugu ◽  
Hiraku Takada ◽  
Tsutomu Katayama ◽  
Hiroko Tsujimoto
Keyword(s):  
Chromosome Replication ◽  
Replication Cycle ◽  
Circular Dna

Bidirectional termination of chromosome replication in Escherichia coli

1973 ◽  
Vol 125 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Peter L. Kuempel ◽  
Patricia Maglothin ◽  
David M. Prescott
Keyword(s):  
Escherichia Coli ◽  
Chromosome Replication
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