scholarly journals Assembly of the replication initiation complex on SV40 origin DNA

2004 ◽  
Vol 32 (3) ◽  
pp. 1103-1112 ◽  
Author(s):  
D. T. Simmons
Keyword(s):  
Replication Initiation ◽  
Initiation Complex ◽  
Sv40 Origin

scholarly journals Topoisomerase I Associates Specifically with Simian Virus 40 Large-T-Antigen Double Hexamer–Origin Complexes

2000 ◽  
Vol 74 (11) ◽  
pp. 5224-5232 ◽  
Author(s):  
Dahai Gai ◽  
Rupa Roy ◽  
Chunxiao Wu ◽  
Daniel T. Simmons
Keyword(s):  
Dna Replication ◽  
Topoisomerase I ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Replication Initiation ◽  
Initiation Complex ◽  
Initiation Of Replication ◽  
Sv40 Origin

ABSTRACT Topoisomerase I (topo I) is required for releasing torsional stress during simian virus 40 (SV40) DNA replication. Recently, it has been demonstrated that topo I participates in initiation of replication as well as in elongation. Although T antigen and topo I can bind to one another in vitro, there is no direct evidence that topo I is a component of the replication initiation complex. We demonstrate in this report that topo I associates with T-antigen double hexamers bound to SV40 origin DNA (TDH) but not to single hexamers. This association has the same nucleotide and DNA requirements as those for the formation of double hexamers on DNA. Interestingly, topo I prefers to bind to fully formed TDH complexes over other oligomerized forms of T antigen associated with the origin. High ratios of topo I to origin DNA destabilize TDH. The partial unwinding of a small-circular-DNA substrate is dependent on the presence of both T antigen and topo I but is inhibited at high topo I concentrations. Competition experiments with a topo I-binding fragment of T antigen indicate that an interaction between T antigen and topo I occurs during the unwinding reaction. We propose that topo I is recruited to the initiation complex after the assembly of TDH and before unwinding to facilitate DNA replication.

scholarly journals The role of DDK and Treslin-MTBP in coordinating replication licensing and pre-Initiation Complex formation

2021 ◽  
Author(s):  
Ilaria Volpi ◽  
Peter J. Gillespie ◽  
Gaganmeet Singh Chadha ◽  
J. Julian Blow
Keyword(s):  
Dna Replication ◽  
Complex Formation ◽  
S Phase ◽  
Replication Initiation ◽  
Initiation Complex ◽  
Crucial Step ◽  
Egg Extract ◽  
Initiation Of Dna Replication ◽  
Rate Limiting

AbstractTreslin/Ticrr is required for the initiation of DNA replication and binds to MTBP (Mdm2 Binding Protein). Here we show that in Xenopus egg extract, MTBP forms an elongated tetramer with Treslin containing two molecules of each protein. Immunodepletion and add-back experiments show that Treslin-MTBP is rate-limiting for replication initiation. It is recruited onto chromatin before S phase starts and recruitment continues during S phase. We show that DDK activity both increases and strengthens the interaction of Treslin-MTBP with licensed chromatin. We also show that DDK activity cooperates with CDK activity to drive the interaction of Treslin-MTBP with TopBP1 which is a regulated crucial step in pre-Initiation Complex formation. These results suggest how DDK works together with CDKs to regulate Treslin-MTBP and plays a crucial in selecting which origins will undergo initiation.

scholarly journals The role of DDK and Treslin–MTBP in coordinating replication licensing and pre-initiation complex formation

Open Biology ◽  
2021 ◽  
Vol 11 (10) ◽  
Author(s):  
Ilaria Volpi ◽  
Peter J. Gillespie ◽  
Gaganmeet Singh Chadha ◽  
J. Julian Blow
Keyword(s):  
Dna Replication ◽  
Complex Formation ◽  
S Phase ◽  
Replication Initiation ◽  
Initiation Complex ◽  
Crucial Step ◽  
Egg Extract ◽  
Initiation Of Dna Replication ◽  
Rate Limiting

Treslin/Ticrr is required for the initiation of DNA replication and binds to MTBP (Mdm2 Binding Protein). Here, we show that in Xenopus egg extract, MTBP forms an elongated tetramer with Treslin containing two molecules of each protein. Immunodepletion and add-back experiments show that Treslin–MTBP is rate limiting for replication initiation. It is recruited onto chromatin before S phase starts and recruitment continues during S phase. We show that DDK activity both increases and strengthens the interaction of Treslin–MTBP with licensed chromatin. We also show that DDK activity cooperates with CDK activity to drive the interaction of Treslin–MTBP with TopBP1 which is a regulated crucial step in pre-initiation complex formation. These results suggest how DDK works together with CDKs to regulate Treslin–MTBP and plays a crucial in selecting which origins will undergo initiation.

scholarly journals Differentiation of the DnaA-oriCSubcomplex for DNA Unwinding in a Replication Initiation Complex

2012 ◽  
Vol 287 (44) ◽  
pp. 37458-37471 ◽  
Author(s):  
Shogo Ozaki ◽  
Yasunori Noguchi ◽  
Yasuhisa Hayashi ◽  
Erika Miyazaki ◽  
Tsutomu Katayama
Keyword(s):  
Replication Initiation ◽  
Dna Unwinding ◽  
Initiation Complex

scholarly journals Near-Atomic Structural Model for Bacterial DNA Replication Initiation Complex and its Functional Insights

2017 ◽  
Vol 112 (3) ◽  
pp. 512a
Author(s):  
Masahiro Shimizu ◽  
Yasunori Noguchi ◽  
Yukari Sakiyama ◽  
Hironori Kawakami ◽  
Tsutomu Katayama ◽  
...  
Keyword(s):  
Dna Replication ◽  
Structural Model ◽  
Replication Initiation ◽  
Initiation Complex ◽  
Bacterial Dna ◽  
Dna Replication Initiation ◽  
Bacterial Dna Replication

DNA polymerase alpha, a component of the replication initiation complex, is essential for the checkpoint coupling S phase to mitosis in fission yeast

1995 ◽  
Vol 108 (9) ◽  
pp. 3109-3118 ◽  
Author(s):  
G. D'Urso ◽  
B. Grallert ◽  
P. Nurse
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerase ◽  
S Phase ◽  
Replication Initiation ◽  
Direct Immunofluorescence ◽  
Temperature Sensitive ◽  
Checkpoint Control ◽  
Initiation Complex ◽  
Dna Polymerase Alpha ◽  
Checkpoint Signal

Genetic analysis in the yeast Schizosaccharomyces pombe has shown that three genes cdc18, cut5, and cdt1, are essential for DNA synthesis and also for the checkpoint control that couples completion of DNA replication to the onset of mitosis. To test whether assembly of the replication initiation complex is an important element in the checkpoint control pathway we have investigated if DNA polymerase alpha (pol1), a component of the initiation complex, is essential for the S-phase checkpoint control. We show that germinating S. pombe spores disrupted for the pol1 gene enter mitosis despite defects in DNA synthesis. This is shown by monitoring septation index, DNA content, and by direct immunofluorescence of mitotic spindles using antibodies to alpha-tubulin. In addition we have isolated six temperature sensitive mutants in the pol1 gene that cause cell cycle arrest when grown at the nonpermissive temperature. Our experiments support a model in which DNA polymerase alpha, in addition to being part of the initiation complex, is required for a checkpoint signal that is activated as cells traverse START, and is essential to prevent mitosis until S phase has been completed. In contrast, proteins responsible for the elongation of DNA may not be necessary for this checkpoint signal.

scholarly journals Near-atomic structural model for bacterial DNA replication initiation complex and its functional insights

2016 ◽  
Vol 113 (50) ◽  
pp. E8021-E8030 ◽  
Author(s):  
Masahiro Shimizu ◽  
Yasunori Noguchi ◽  
Yukari Sakiyama ◽  
Hironori Kawakami ◽  
Tsutomu Katayama ◽  
...  
Keyword(s):  
Dna Replication ◽  
Structural Model ◽  
Replication Initiation ◽  
Dna Looping ◽  
Dna Unwinding ◽  
Initiation Complex ◽  
Dna Replication Initiation ◽  
Left And Right ◽  
Dynamic Structures ◽  
Domain Iii

Upon DNA replication initiation in Escherichia coli, the initiator protein DnaA forms higher-order complexes with the chromosomal origin oriC and a DNA-bending protein IHF. Although tertiary structures of DnaA and IHF have previously been elucidated, dynamic structures of oriC–DnaA–IHF complexes remain unknown. Here, combining computer simulations with biochemical assays, we obtained models at almost-atomic resolution for the central part of the oriC–DnaA–IHF complex. This complex can be divided into three subcomplexes; the left and right subcomplexes include pentameric DnaA bound in a head-to-tail manner and the middle subcomplex contains only a single DnaA. In the left and right subcomplexes, DnaA ATPases associated with various cellular activities (AAA+) domain III formed helices with specific structural differences in interdomain orientations, provoking a bend in the bound DNA. In the left subcomplex a continuous DnaA chain exists, including insertion of IHF into the DNA looping, consistent with the DNA unwinding function of the complex. The intervening spaces in those subcomplexes are crucial for DNA unwinding and loading of DnaB helicases. Taken together, this model provides a reasonable near-atomic level structural solution of the initiation complex, including the dynamic conformations and spatial arrangements of DnaA subcomplexes.

scholarly journals Crystal structures of two intermediates in the assembly of the papillomavirus replication initiation complex

2002 ◽  
Vol 21 (6) ◽  
pp. 1487-1496 ◽  
Author(s):  
Eric J. Enemark ◽  
Arne Stenlund ◽  
Leemor Joshua-Tor
Keyword(s):  
Crystal Structures ◽  
Replication Initiation ◽  
Initiation Complex
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