Association of cyclin A and cdk2 with SV40 DNA in replication initiation complexes is cell cycle dependent

Chromosoma ◽  
1997 ◽  
Vol 105 (6) ◽  
pp. 349-359 ◽  
Author(s):  
Dominique Cannella ◽  
James M. Roberts ◽  
Rati Fotedar
Keyword(s):  
Cell Cycle ◽  
Cyclin A ◽  
Replication Initiation ◽  
Cycle Dependent ◽  
Sv40 Dna

Association of cyclin A and cdk2 with SV40 DNA in replication initiation complexes is cell cycle dependent

Chromosoma ◽  
1997 ◽  
Vol 105 (6) ◽  
pp. 349-359 ◽  
Author(s):  
Dominique Cannella ◽  
James M. Roberts ◽  
Rati Fotedar
Keyword(s):  
Cell Cycle ◽  
Cyclin A ◽  
Replication Initiation ◽  
Cycle Dependent ◽  
Sv40 Dna

scholarly journals Cell Cycle-Dependent Switch of TopBP1 Functions by Cdk2 and Akt

2020 ◽  
Vol 40 (8) ◽  
Author(s):  
Kang Liu ◽  
Joshua D. Graves ◽  
Yu-Ju Lee ◽  
Fang-Tsyr Lin ◽  
Weei-Chin Lin
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Cancer Cells ◽  
Cyclin A ◽  
Replication Initiation ◽  
Dna Replication Initiation ◽  
Cycle Dependent

ABSTRACT Cdk2-dependent TopBP1-treslin interaction is critical for DNA replication initiation. However, it remains unclear how this association is terminated after replication initiation is finished. Here, we demonstrate that phosphorylation of TopBP1 by Akt coincides with cyclin A activation during S and G2 phases and switches the TopBP1-interacting partner from treslin to E2F1, which results in the termination of replication initiation. Premature activation of Akt in G1 phase causes an early switch and inhibits DNA replication. TopBP1 is often overexpressed in cancer and can bypass control by Cdk2 to interact with treslin, leading to enhanced DNA replication. Consistent with this notion, reducing the levels of TopBP1 in cancer cells restores sensitivity to a Cdk2 inhibitor. Together, our study links Cdk2 and Akt pathways to the control of DNA replication through the regulation of TopBP1-treslin interaction. These data also suggest an important role for TopBP1 in driving abnormal DNA replication in cancer.

scholarly journals Enhancement of DNA-mediated gene transfer by high-Mr carrier DNA in synchronized CV-1 cells

1985 ◽  
Vol 225 (2) ◽  
pp. 529-533 ◽  
Author(s):  
A J Strain ◽  
W A H Wallace ◽  
A H Wyllie
Keyword(s):  
Cell Cycle ◽  
Gene Transfer ◽  
Transfection Efficiency ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
S Phase ◽  
Sv40 Virus ◽  
G2 Phase ◽  
Cycle Dependent ◽  
Sv40 Dna

Synchronized CV-1 cells were transfected with SV40 (simian virus 40) DNA-calcium phosphate co-precipitates. In the presence of carrier DNA, the transfection efficiency of SV40 DNA was decreased 5-fold in S-phase cells and was increased 4-fold in preparations of mitotically enriched cells as compared with asynchronous controls. No difference was observed when carrier DNA was omitted, when cells had progressed through S-phase and into G2-phase, or when the infectivity of cells to intact SV40 virus was tested. These results highlight the importance of cell-cycle-dependent factors on DNA-mediated gene transfer.

scholarly journals Human cyclins A and B1 are differentially located in the cell and undergo cell cycle-dependent nuclear transport.

1991 ◽  
Vol 115 (1) ◽  
pp. 1-17 ◽  
Author(s):  
J Pines ◽  
T Hunter
Keyword(s):  
Cell Cycle ◽  
Human Fibroblasts ◽  
Nuclear Lamina ◽  
Cyclin A ◽  
Cyclin B1 ◽  
Cell Fractionation ◽  
Mitotic Apparatus ◽  
Epithelial Tumor ◽  
Mitotic Cyclin ◽  
Cycle Dependent

We have used immunofluorescence staining to study the subcellular distribution of cyclin A and B1 during the somatic cell cycle. In both primary human fibroblasts and in epithelial tumor cells, we find that cyclin A is predominantly nuclear from S phase onwards. Cyclin A may associated with condensing chromosomes in prophase, but is not associated with condensed chromosomes in metaphase. By contrast, cyclin B1 accumulates in the cytoplasm of interphase cells and only enters the nucleus at the beginning of mitosis, before nuclear lamina breakdown. In mitotic cells, cyclin B1 associates with condensed chromosomes in prophase and metaphase, and with the mitotic apparatus. Cyclin A is degraded during metaphase and cyclin B1 is precipitously destroyed at the metaphase----anaphase transition. Cell fractionation and immunoprecipitation studies showed that both cyclin A and cyclin B1 are associated with PSTAIRE-containing proteins. The nuclear, but not the cytoplasmic form, of cyclin A is associated with a 33-kD PSTAIRE-containing protein. Cyclin B1 is associated with p34cdc2 in the cytoplasm. Thus we propose that the different localization of cyclin A and cyclin B1 in the cell cycle could be the means by which the two types of mitotic cyclin confer substrate specificity upon their associated PSTAIRE-containing protein kinase subunit.

scholarly journals Differential Control of Transcription by DNA-bound Cyclins

2001 ◽  
Vol 12 (7) ◽  
pp. 2207-2217 ◽  
Author(s):  
Tae-You Kim ◽  
William G. Kaelin
Keyword(s):  
Cell Cycle ◽  
Dna Binding ◽  
Cyclin E ◽  
Cyclin A ◽  
Dependent Manner ◽  
Dna Binding Domain ◽  
Transcriptional Modulators ◽  
A Cell ◽  
Cycle Dependent ◽  
Differential Control

Different cyclins mediate different cell-cycle transitions. Some cyclins, such as cyclin A and cyclin E, form stable complexes with proteins that bind directly or indirectly to DNA and thus might be recruited to certain regions of the genome at specific times in the cell cycle. Furthermore, cyclins contain structural motifs that are also present in known transcriptional modulators. We found that cyclin A is a potent transcriptional repressor and cyclin E is a potent transcriptional activator when bound to DNA via a heterologous DNA binding domain. The former activity was linked to the integrity of the cyclin A cyclin fold, whereas the latter activity related to the ability of cyclin E to activate cdk2 and recognize substrates. Furthermore, we found that cyclin E, but not cyclin A, activated transcription in a cell-cycle–dependent manner when present in physiological concentrations as an unfused protein. These results suggest that cyclin A and cyclin E intrinsically differ with respect to their ability to modulate transcription when tethered to DNA.

Cyclin A-Cys41 does not undergo cell cycle-dependent degradation in Xenopus extracts

FEBS Letters ◽  
1992 ◽  
Vol 306 (1) ◽  
pp. 90-93 ◽  
Author(s):  
Thierry Lorca ◽  
Alain Devault ◽  
Pierre Colas ◽  
André Van Loon ◽  
Didier Fesquet ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cyclin A ◽  
Cycle Dependent

scholarly journals Whole-Genome Analysis Reveals That the Nucleoid Protein IHF Predominantly Binds to the Replication Origin oriC Specifically at the Time of Initiation

2021 ◽  
Vol 12 ◽  
Author(s):  
Kazutoshi Kasho ◽  
Taku Oshima ◽  
Onuma Chumsakul ◽  
Kensuke Nakamura ◽  
Kazuki Fukamachi ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Replication Origin ◽  
High Throughput Sequencing ◽  
Dna Supercoiling ◽  
Integration Host Factor ◽  
Replication Initiation ◽  
Whole Genome Analysis ◽  
Bacterial Chromosomes ◽  
Underlying Mechanisms ◽  
Cycle Dependent

The structure and function of bacterial chromosomes are dynamically regulated by a wide variety of nucleoid-associated proteins (NAPs) and DNA superstructures, such as DNA supercoiling. In Escherichia coli, integration host factor (IHF), a NAP, binds to specific transcription promoters and regulatory DNA elements of DNA replication such as the replication origin oriC: binding to these elements depends on the cell cycle but underlying mechanisms are unknown. In this study, we combined GeF-seq (genome footprinting with high-throughput sequencing) with synchronization of the E. coli cell cycle to determine the genome-wide, cell cycle-dependent binding of IHF with base-pair resolution. The GeF-seq results in this study were qualified enough to analyze genomic IHF binding sites (e.g., oriC and the transcriptional promoters of ilvG and osmY) except some of the known sites. Unexpectedly, we found that before replication initiation, oriC was a predominant site for stable IHF binding, whereas all other loci exhibited reduced IHF binding. To reveal the specific mechanism of stable oriC–IHF binding, we inserted a truncated oriC sequence in the terC (replication terminus) locus of the genome. Before replication initiation, stable IHF binding was detected even at this additional oriC site, dependent on the specific DnaA-binding sequence DnaA box R1 within the site. DnaA oligomers formed on oriC might protect the oriC–IHF complex from IHF dissociation. After replication initiation, IHF rapidly dissociated from oriC, and IHF binding to other sites was sustained or stimulated. In addition, we identified a novel locus associated with cell cycle-dependent IHF binding. These findings provide mechanistic insight into IHF binding and dissociation in the genome.

scholarly journals Phosphorylation of Simian Virus 40 T Antigen on Thr 124 Selectively Promotes Double-Hexamer Formation on Subfragments of the Viral Core Origin

2000 ◽  
Vol 74 (18) ◽  
pp. 8601-8613 ◽  
Author(s):  
Brett A. Barbaro ◽  
K. R. Sreekumar ◽  
Danielle R. Winters ◽  
Andrea E. Prack ◽  
Peter A. Bullock
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Cell Cycle Control ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Large Tumor ◽  
Sv40 Origin ◽  
Cycle Dependent ◽  
Sv40 Dna

ABSTRACT Cell cycle-dependent phosphorylation of simian virus 40 (SV40) large tumor antigen (T-ag) on threonine 124 is essential for the initiation of viral DNA replication. A T-ag molecule containing a Thr→Ala substitution at this position (T124A) was previously shown to bind to the SV40 core origin but to be defective in DNA unwinding and initiation of DNA replication. However, exactly what step in the initiation process is defective as a result of the T124A mutation has not been established. Therefore, to better understand the control of SV40 replication, we have reinvestigated the assembly of T124A molecules on the SV40 origin. Herein it is demonstrated that hexamer formation is unaffected by the phosphorylation state of Thr 124. In contrast, T124A molecules are defective in double-hexamer assembly on subfragments of the core origin containing single assembly units. We also report that T124A molecules are inhibitors of T-ag double hexamer formation. These and related studies indicate that phosphorylation of T-ag on Thr 124 is a necessary step for completing the assembly of functional double hexamers on the SV40 origin. The implications of these studies for the cell cycle control of SV40 DNA replication are discussed.

scholarly journals Cell Cycle-Dependent Regulation of Human DNA Polymerase α-Primase Activity by Phosphorylation

1999 ◽  
Vol 19 (1) ◽  
pp. 646-656 ◽  
Author(s):  
Christian Voitenleitner ◽  
Christoph Rehfuess ◽  
Melissa Hilmes ◽  
Lynda O’Rear ◽  
Pao-Chi Liao ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Polymerase ◽  
Cyclin E ◽  
Cyclin A ◽  
Human Cells ◽  
Dependent Manner ◽  
Dna Polymerase Α ◽  
A Cell ◽  
Cycle Dependent

ABSTRACT DNA polymerase α-primase is known to be phosphorylated in human and yeast cells in a cell cycle-dependent manner on the p180 and p68 subunits. Here we show that phosphorylation of purified human DNA polymerase α-primase by purified cyclin A/cdk2 in vitro reduced its ability to initiate simian virus 40 (SV40) DNA replication in vitro, while phosphorylation by cyclin E/cdk2 stimulated its initiation activity. Tryptic phosphopeptide mapping revealed a family of p68 peptides that was modified well by cyclin A/cdk2 and poorly by cyclin E/cdk2. The p180 phosphopeptides were identical with both kinases. By mass spectrometry, the p68 peptide family was identified as residues 141 to 160. Cyclin A/cdk2- and cyclin A/cdc2-modified p68 also displayed a phosphorylation-dependent shift to slower electrophoretic mobility. Mutation of the four putative phosphorylation sites within p68 peptide residues 141 to 160 prevented its phosphorylation by cyclin A/cdk2 and the inhibition of replication activity. Phosphopeptide maps of the p68 subunit of DNA polymerase α-primase from human cells, synchronized and labeled in G1/S and in G2, revealed a cyclin E/cdk2-like pattern in G1/S and a cyclin A/cdk2-like pattern in G2. The slower-electrophoretic-mobility form of p68 was absent in human cells in G1/S and appeared as the cells entered G2/M. Consistent with this, the ability of DNA polymerase α-primase isolated from synchronized human cells to initiate SV40 replication was maximal in G1/S, decreased as the cells completed S phase, and reached a minimum in G2/M. These results suggest that the replication activity of DNA polymerase α-primase in human cells is regulated by phosphorylation in a cell cycle-dependent manner.

scholarly journals Activation of the p34 CDC2 protein kinase at the start of S phase in the human cell cycle.

1992 ◽  
Vol 3 (4) ◽  
pp. 389-401 ◽  
Author(s):  
R L Marraccino ◽  
E J Firpo ◽  
J M Roberts
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Cyclin A ◽  
S Phase ◽  
Cdc2 Kinase ◽  
G1 Cells ◽  
Sv40 Dna ◽  
P34 Cdc2

Using a protocol for selecting cells on the basis of both size and age (with respect to the preceding mitosis), we isolated highly synchronous human G1 cells. With this procedure, we demonstrated that the p34 CDC2 kinase was activated at the start of S phase. Cyclin A synthesis began at the same time, and activation of the p34 CDC2 kinase at the start of S phase was, at least in part, due to its association with cyclin A. Furthermore, cells synchronized in late G1 by exposure to the drug mimosine contain active cyclin A/p34 CDC2 kinase, indicating that p34 CDC2 activation can occur before DNA synthesis begins. Thus, the cyclin A/CDC2 complex, which previously has been shown to be sufficient to start SV40 DNA synthesis in vitro, assembles and is activated at the start of S phase in vivo.

Sign in / Sign up

Export Citation Format

Share Document