scholarly journals The human checkpoint Rad protein Rad17 is chromatin-associated throughout the cell cycle, localizes to DNA replication sites, and interacts with DNA polymerase  

2003 ◽  
Vol 31 (19) ◽  
pp. 5568-5575 ◽  
Author(s):  
S. M. Post
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Dna Polymerase ◽  
Replication Sites

scholarly journals Cell cycle localization dynamics of mitochondrial DNA polymerase IC in African trypanosomes

2018 ◽  
Vol 29 (21) ◽  
pp. 2540-2552 ◽  
Author(s):  
Jeniffer Concepción-Acevedo ◽  
Jonathan C. Miller ◽  
Michael J. Boucher ◽  
Michele M. Klingbeil
Keyword(s):  
Cell Cycle ◽  
Mitochondrial Dna ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Dynamic Environment ◽  
African Trypanosomes ◽  
Protein Levels ◽  
Replication Sites ◽  
Cycle Dependent ◽  
Mitochondrial Dna Polymerase

Trypanosoma brucei has a unique catenated mitochondrial DNA (mtDNA) network called kinetoplast DNA (kDNA). Replication of kDNA occurs once per cell cycle in near synchrony with nuclear S phase and requires the coordination of many proteins. Among these are three essential DNA polymerases (TbPOLIB, IC, and ID). Localization dynamics of these proteins with respect to kDNA replication stages and how they coordinate their functions during replication are not well understood. We previously demonstrated that TbPOLID undergoes dynamic localization changes that are coupled to kDNA replication events. Here, we report the localization of TbPOLIC, a second essential DNA polymerase, and demonstrate the accumulation of TbPOLIC foci at active kDNA replication sites (antipodal sites) during stage II of the kDNA duplication cycle. While TbPOLIC was undetectable by immunofluorescence during other cell cycle stages, steady-state protein levels measured by Western blot remained constant. TbPOLIC foci colocalized with the fraction of TbPOLID that localized to the antipodal sites. However, the partial colocalization of the two essential DNA polymerases suggests a highly dynamic environment at the antipodal sites to coordinate the trafficking of replication proteins during kDNA synthesis. These data indicate that cell cycle–dependent localization is a major regulatory mechanism for essential mtDNA polymerases during kDNA replication.

scholarly journals Cell cycle-dependent phosphorylation and dephosphorylation of the yeast DNA polymerase alpha-primase B subunit.

1995 ◽  
Vol 15 (2) ◽  
pp. 883-891 ◽  
Author(s):  
M Foiani ◽  
G Liberi ◽  
G Lucchini ◽  
P Plevani
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Dna Polymerase ◽  
Posttranslational Modifications ◽  
S Phase ◽  
Dna Polymerase Alpha ◽  
B Subunit ◽  
Initiation Of Dna Replication ◽  
Cycle Dependent

The yeast DNA polymerase alpha-primase B subunit functions in initiation of DNA replication. This protein is present in two forms, of 86 and 91 kDa, and the p91 polypeptide results from cell cycle-regulated phosphorylation of p86. The B subunit present in G1 arises by dephosphorylation of p91 while cells are exiting from mitosis, becomes phosphorylated in early S phase, and is competent and sufficient to initiate DNA replication. The B subunit transiently synthesized as a consequence of periodic transcription of the POL12 gene is phosphorylated no earlier than G2. Phosphorylation of the B subunit does not require execution of the CDC7-dependent step and ongoing DNA synthesis. We suggest that posttranslational modifications of the B subunit might modulate the role of DNA polymerase alpha-primase in DNA replication.

scholarly journals Replication and Control of Circular Bacterial Plasmids

1998 ◽  
Vol 62 (2) ◽  
pp. 434-464 ◽  
Author(s):  
Gloria del Solar ◽  
Rafael Giraldo ◽  
María Jesús Ruiz-Echevarría ◽  
Manuel Espinosa ◽  
Ramón Díaz-Orejas
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Dna Polymerase ◽  
Dna Sequences ◽  
Antisense Rna ◽  
Bacterial Population ◽  
Replication Initiation ◽  
Plasmid Replication ◽  
Genetic Elements ◽  
Bacterial Plasmids

SUMMARY An essential feature of bacterial plasmids is their ability to replicate as autonomous genetic elements in a controlled way within the host. Therefore, they can be used to explore the mechanisms involved in DNA replication and to analyze the different strategies that couple DNA replication to other critical events in the cell cycle. In this review, we focus on replication and its control in circular plasmids. Plasmid replication can be conveniently divided into three stages: initiation, elongation, and termination. The inability of DNA polymerases to initiate de novo replication makes necessary the independent generation of a primer. This is solved, in circular plasmids, by two main strategies: (i) opening of the strands followed by RNA priming (theta and strand displacement replication) or (ii) cleavage of one of the DNA strands to generate a 3′-OH end (rolling-circle replication). Initiation is catalyzed most frequently by one or a few plasmid-encoded initiation proteins that recognize plasmid-specific DNA sequences and determine the point from which replication starts (the origin of replication). In some cases, these proteins also participate directly in the generation of the primer. These initiators can also play the role of pilot proteins that guide the assembly of the host replisome at the plasmid origin. Elongation of plasmid replication is carried out basically by DNA polymerase III holoenzyme (and, in some cases, by DNA polymerase I at an early stage), with the participation of other host proteins that form the replisome. Termination of replication has specific requirements and implications for reinitiation, studies of which have started. The initiation stage plays an additional role: it is the stage at which mechanisms controlling replication operate. The objective of this control is to maintain a fixed concentration of plasmid molecules in a growing bacterial population (duplication of the plasmid pool paced with duplication of the bacterial population). The molecules involved directly in this control can be (i) RNA (antisense RNA), (ii) DNA sequences (iterons), or (iii) antisense RNA and proteins acting in concert. The control elements maintain an average frequency of one plasmid replication per plasmid copy per cell cycle and can “sense” and correct deviations from this average. Most of the current knowledge on plasmid replication and its control is based on the results of analyses performed with pure cultures under steady-state growth conditions. This knowledge sets important parameters needed to understand the maintenance of these genetic elements in mixed populations and under environmental conditions.

scholarly journals p21CDKN1A Does Not Interfere with Loading of PCNA at DNA Replication Sites, but Inhibits Subsequent Binding of DNA Polymerase D at the G1/S Phase Transition

Cell Cycle ◽  
2003 ◽  
Vol 2 (6) ◽  
pp. 595-602 ◽  
Author(s):  
Ornella Cazzalini ◽  
Paola Perucca ◽  
Federica Riva ◽  
Lucia A. Stivala ◽  
Livia Bianchi ◽  
...  
Keyword(s):  
Phase Transition ◽  
Dna Replication ◽  
Dna Polymerase ◽  
S Phase ◽  
Replication Sites

scholarly journals Novel Role for Cdc14 Sequestration: Cdc14 Dephosphorylates Factors That Promote DNA Replication

2006 ◽  
Vol 27 (3) ◽  
pp. 842-853 ◽  
Author(s):  
Joanna Bloom ◽  
Frederick R. Cross
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Dna Polymerase ◽  
Budding Yeast ◽  
S Phase ◽  
Mitotic Exit ◽  
Checkpoint Protein ◽  
Replication Factors ◽  
Established Role

ABSTRACT The phosphatase Cdc14 is required for mitotic exit in budding yeast. Cdc14 promotes Cdk1 inactivation by targeting proteins that, when dephosphorylated, trigger degradation of mitotic cyclins and accumulation of the Cdk1 inhibitor, Sic1. Cdc14 is sequestered in the nucleolus during most of the cell cycle but is released into the nucleus and cytoplasm during anaphase. When Cdc14 is not properly sequestered in the nucleolus, expression of the S-phase cyclin Clb5 is required for viability, suggesting that the antagonizing activity of Clb5-dependent Cdk1 specifically is necessary when Cdc14 is delocalized. We show that delocalization of Cdc14 combined with loss of Clb5 causes defects in DNA replication. When Cdc14 is not sequestered, it efficiently dephosphorylates a subset of Cdk1 substrates including the replication factors, Sld2 and Dpb2. Mutations causing Cdc14 mislocalization interact genetically with mutations affecting the function of DNA polymerase ε and the S-phase checkpoint protein Mec1. Our findings suggest that Cdc14 is retained in the nucleolus to support a favorable kinase/phosphatase balance while cells are replicating their DNA, in addition to the established role of Cdc14 sequestration in coordinating nuclear segregation with mitotic exit.

scholarly journals A Mutation in DNA Polymerase α Rescues WEE1KO Sensitivity to HU

2021 ◽  
Vol 22 (17) ◽  
pp. 9409
Author(s):  
Thomas Eekhout ◽  
José Antonio Pedroza-Garcia ◽  
Pooneh Kalhorzadeh ◽  
Geert De Jaeger ◽  
Lieven De Veylder
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Dna Polymerase ◽  
Driving Force ◽  
S Phase ◽  
Catalytic Subunit ◽  
Genomic Integrity ◽  
Cyclin Dependent Kinases ◽  
Dna Polymerase Α ◽  
Wee1 Kinase

During DNA replication, the WEE1 kinase is responsible for safeguarding genomic integrity by phosphorylating and thus inhibiting cyclin-dependent kinases (CDKs), which are the driving force of the cell cycle. Consequentially, wee1 mutant plants fail to respond properly to problems arising during DNA replication and are hypersensitive to replication stress. Here, we report the identification of the polα-2 mutant, mutated in the catalytic subunit of DNA polymerase α, as a suppressor mutant of wee1. The mutated protein appears to be less stable, causing a loss of interaction with its subunits and resulting in a prolonged S-phase.

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