scholarly journals Dynamic properties of nuclear lamins: lamin B is associated with sites of DNA replication.

1994 ◽  
Vol 125 (6) ◽  
pp. 1201-1212 ◽  
Author(s):  
R D Moir ◽  
M Montag-Lowy ◽  
R D Goldman
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Dynamic Properties ◽  
Nuclear Lamina ◽  
S Phase ◽  
Nuclear Antigen ◽  
Nuclear Staining ◽  
Lamin B ◽  
Nuclear Lamins ◽  
Proliferating Cell

The nuclear lamins form a fibrous structure, the nuclear lamina, at the periphery of the nucleus. Recent results suggest that lamins are also present as foci or spots in the nucleoplasm at various times during interphase of the cell cycle (Goldman, A. E., R. D. Moir, M. Montag-Lowy, M. Stewart, and R. D. Goldman. 1992. J. Cell Biol. 104:725-732; Bridger, J. M., I. R. Kill, M. O'Farrell, and C. J. Hutchison. 1993. J. Cell Sci. 104:297-306). In this report we demonstrate that during mid-late S-phase, nuclear foci detected with lamin B antibodies are coincident with sites of DNA replication as detected by the colocalization of sites of incorporation of bromodeoxyuridine (BrDU) or proliferating cell nuclear antigen (PCNA). The relationship between lamin B and BrDU is not maintained in the following G1 stage of the cell cycle. Furthermore, the nuclear staining patterns seen with antibodies directed against lamins A and C in mid-late S-phase do not coalign with the lamin B/BrDU-containing structures. These results imply that there is a role for lamin B in the organization of replicating chromatin during S phase.

scholarly journals The distribution pattern of proliferating cell nuclear antigen in the nuclei of Leishmania donovani

Microbiology ◽  
2009 ◽  
Vol 155 (11) ◽  
pp. 3748-3757 ◽  
Author(s):  
Devanand Kumar ◽  
Neha Minocha ◽  
Kalpana Rajanala ◽  
Swati Saha
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Proliferating Cell Nuclear Antigen ◽  
Cell Cycle Progression ◽  
Leishmania Donovani ◽  
Systemic Disease ◽  
S Phase ◽  
Nuclear Antigen ◽  
M Phase ◽  
Proliferating Cell

DNA replication in eukaryotes is a highly conserved process marked by the licensing of multiple origins, with pre-replication complex assembly in G1 phase, followed by the onset of replication at these origins in S phase. The two strands replicate by different mechanisms, and DNA synthesis is brought about by the activity of the replicative DNA polymerases Pol δ and Pol ϵ. Proliferating cell nuclear antigen (PCNA) augments the processivity of these polymerases by serving as a DNA sliding clamp protein. This study reports the cloning of PCNA from the protozoan Leishmania donovani, which is the causative agent of the systemic disease visceral leishmaniasis. PCNA was demonstrated to be robustly expressed in actively proliferating L. donovani promastigotes. We found that the protein was present primarily in the nucleus throughout the cell cycle, and it was found in both proliferating procyclic and metacyclic promastigotes. However, levels of expression of PCNA varied through cell cycle progression, with maximum expression evident in G1 and S phases. The subnuclear pattern of expression of PCNA differed in different stages of the cell cycle; it formed distinct subnuclear foci in S phase, while it was distributed in a more diffuse pattern in G2/M phase and post-mitotic phase cells. These subnuclear foci are the sites of active DNA replication, suggesting that replication factories exist in Leishmania, as they do in higher eukaryotes, thus opening avenues for investigating other Leishmania proteins that are involved in DNA replication as part of these replication factories.

scholarly journals Regulation of DNA Replication Licensing and Re-Replication by Cdt1

2021 ◽  
Vol 22 (10) ◽  
pp. 5195
Author(s):  
Hui Zhang
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Replication ◽  
Genome Stability ◽  
E3 Ligase ◽  
S Phase ◽  
Replication Initiation ◽  
Nuclear Antigen ◽  
Repair Synthesis ◽  
Ubiquitin E3 Ligase

In eukaryotic cells, DNA replication licensing is precisely regulated to ensure that the initiation of genomic DNA replication in S phase occurs once and only once for each mitotic cell division. A key regulatory mechanism by which DNA re-replication is suppressed is the S phase-dependent proteolysis of Cdt1, an essential replication protein for licensing DNA replication origins by loading the Mcm2-7 replication helicase for DNA duplication in S phase. Cdt1 degradation is mediated by CRL4Cdt2 ubiquitin E3 ligase, which further requires Cdt1 binding to proliferating cell nuclear antigen (PCNA) through a PIP box domain in Cdt1 during DNA synthesis. Recent studies found that Cdt2, the specific subunit of CRL4Cdt2 ubiquitin E3 ligase that targets Cdt1 for degradation, also contains an evolutionarily conserved PIP box-like domain that mediates the interaction with PCNA. These findings suggest that the initiation and elongation of DNA replication or DNA damage-induced repair synthesis provide a novel mechanism by which Cdt1 and CRL4Cdt2 are both recruited onto the trimeric PCNA clamp encircling the replicating DNA strands to promote the interaction between Cdt1 and CRL4Cdt2. The proximity of PCNA-bound Cdt1 to CRL4Cdt2 facilitates the destruction of Cdt1 in response to DNA damage or after DNA replication initiation to prevent DNA re-replication in the cell cycle. CRL4Cdt2 ubiquitin E3 ligase may also regulate the degradation of other PIP box-containing proteins, such as CDK inhibitor p21 and histone methylase Set8, to regulate DNA replication licensing, cell cycle progression, DNA repair, and genome stability by directly interacting with PCNA during DNA replication and repair synthesis.

scholarly journals Effect of Proliferating Cell Nuclear Antigen Ubiquitination and Chromatin Structure on the Dynamic Properties of the Y-family DNA Polymerases

2008 ◽  
Vol 19 (12) ◽  
pp. 5193-5202 ◽  
Author(s):  
Simone Sabbioneda ◽  
Audrey M. Gourdin ◽  
Catherine M. Green ◽  
Angelika Zotter ◽  
Giuseppina Giglia-Mari ◽  
...  
Keyword(s):  
Chromatin Structure ◽  
Proliferating Cell Nuclear Antigen ◽  
Dynamic Properties ◽  
Human Fibroblasts ◽  
Dna Polymerases ◽  
S Phase ◽  
Nuclear Antigen ◽  
Replication Foci ◽  
Y Family ◽  
Proliferating Cell

Y-family DNA polymerases carry out translesion synthesis past damaged DNA. DNA polymerases (pol) η and ι are usually uniformly distributed through the nucleus but accumulate in replication foci during S phase. DNA-damaging treatments result in an increase in S phase cells containing polymerase foci. Using photobleaching techniques, we show that polη is highly mobile in human fibroblasts. Even when localized in replication foci, it is only transiently immobilized. Although ubiquitination of proliferating cell nuclear antigen (PCNA) is not required for the localization of polη in foci, it results in an increased residence time in foci. polι is even more mobile than polη, both when uniformly distributed and when localized in foci. Kinetic modeling suggests that both polη and polι diffuse through the cell but that they are transiently immobilized for ∼150 ms, with a larger proportion of polη than polι immobilized at any time. Treatment of cells with DRAQ5, which results in temporary opening of the chromatin structure, causes a dramatic immobilization of polη but not polι. Our data are consistent with a model in which the polymerases are transiently probing the DNA/chromatin. When DNA is exposed at replication forks, the polymerase residence times increase, and this is further facilitated by the ubiquitination of PCNA.

scholarly journals Existence of two populations of cyclin/proliferating cell nuclear antigen during the cell cycle: association with DNA replication sites.

1987 ◽  
Vol 105 (4) ◽  
pp. 1549-1554 ◽  
Author(s):  
R Bravo ◽  
H Macdonald-Bravo
Keyword(s):  
Dna Replication ◽  
Dna Synthesis ◽  
S Phase ◽  
Nuclear Antigen ◽  
Dna Polymerase Delta ◽  
Quiescent Cells ◽  
Replication Sites ◽  
Nuclear Structures ◽  
Proliferating Cell ◽  
Two Populations

Pulse-chase experiments have revealed that cyclin, the auxiliary protein of DNA polymerase-delta, is stable during the transition from growth to quiescence in 3T3 cells. Immunoblotting together with immunofluorescence analysis has shown that the amount of cyclin after 24 h of quiescence is 30-40% of that of growing cells and that it presents a nucleoplasmic staining. Immunofluorescence studies show the existence of two populations of cyclin during the S phase, one that is nucleoplasmic as in quiescent cells and is easily extracted by detergent, and another that is associated to specific nuclear structures. By using antibromodeoxyuridine immunofluorescence to detect the sites of DNA synthesis, it was shown that the staining patterns of the replicon clusters and their order of appearance throughout the S phase are identical to those observed for cyclin. Two-dimensional gel analysis of Triton-extracted cells show that 20-30% of cyclin remains associated with the replicon clusters. This population of cyclin could not be released from the nucleus using high-salt extractions. This demonstrates that cyclin is tightly associated to the sites of DNA replication and that it must have a fundamental role in DNA synthesis in eukaryotic cells.

scholarly journals Pivotal roles of PCNA loading and unloading in heterochromatin function

2018 ◽  
Vol 115 (9) ◽  
pp. E2030-E2039 ◽  
Author(s):  
Ryan Janke ◽  
Grant A. King ◽  
Martin Kupiec ◽  
Jasper Rine
Keyword(s):  
Dna Replication ◽  
Proliferating Cell Nuclear Antigen ◽  
Transcriptional Silencing ◽  
S Phase ◽  
Nuclear Antigen ◽  
Histone Chaperones ◽  
Replication Forks ◽  
Nucleosome Assembly ◽  
Loading And Unloading ◽  
Proliferating Cell

In Saccharomyces cerevisiae, heterochromatin structures required for transcriptional silencing of the HML and HMR loci are duplicated in coordination with passing DNA replication forks. Despite major reorganization of chromatin structure, the heterochromatic, transcriptionally silent states of HML and HMR are successfully maintained throughout S-phase. Mutations of specific components of the replisome diminish the capacity to maintain silencing of HML and HMR through replication. Similarly, mutations in histone chaperones involved in replication-coupled nucleosome assembly reduce gene silencing. Bridging these observations, we determined that the proliferating cell nuclear antigen (PCNA) unloading activity of Elg1 was important for coordinating DNA replication forks with the process of replication-coupled nucleosome assembly to maintain silencing of HML and HMR through S-phase. Collectively, these data identified a mechanism by which chromatin reassembly is coordinated with DNA replication to maintain silencing through S-phase.

The cell-cycle regulated proliferating cell nuclear antigen is required for SV40 DNA replication in vitro

Nature ◽  
1987 ◽  
Vol 326 (6112) ◽  
pp. 471-475 ◽  
Author(s):  
Gregory Prelich ◽  
Matthew Kostura ◽  
Daniel R. Marshak ◽  
Michael B. Mathews ◽  
Bruce Stillman
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Proliferating Cell Nuclear Antigen ◽  
Nuclear Antigen ◽  
Sv40 Dna ◽  
Proliferating Cell

scholarly journals Yes-associated protein regulates podocyte cell cycle re-entry and dedifferentiation in adriamycin-induced nephropathy

2019 ◽  
Vol 10 (12) ◽  
Author(s):  
Kewei Xie ◽  
Chenqi Xu ◽  
Minfang Zhang ◽  
Minzhou Wang ◽  
Lulin Min ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
S Phase ◽  
Nuclear Antigen ◽  
Over Expression ◽  
Differentiated Cells ◽  
Marker Proteins ◽  
Proliferating Cell

AbstractPodocytes are terminally differentiated cells with little proliferative capacity. The high expression levels of cell cycle inhibitory proteins, including p21, p27, and p57, play an important role in maintaining the low level of proliferation of mature podocytes. In the present study, we aimed to explore the role of yes-associated protein (YAP) signalling in adriamycin-induced podocyte re-entry into the cell cycle and dedifferentiation. Proliferating cell nuclear antigen (PCNA)-, cyclin-dependent kinase 4 (CDK4)-, and Cyclin D1-positive podocytes were found in mice with adriamycin-induced nephropathy. In vitro, adriamycin administration increased the percentage of cells in S phase and the upregulation of mesenchymal-related marker proteins. CDK4 and cyclin D1 were significantly up-regulated after incubation with adriamycin. Overexpression of YAP in podocytes promoted their entry into the cell cycle; up-regulated cyclin D1, desmin, and snail2 expression and down-regulated Wilms’ tumour 1 (WT1) and nephrin production. Recombinant murine FGF-basic induced podocytes to re-enter the cell cycle, inhibited WT1 and nephrin, and increased desmin and snail2 expression. Pretreating podocytes with verteporfin, an inhibitor of YAP/ TEA domain transcription factor (TEAD), decreased the adriamycin-induced overexpression of cyclin D1 and reduced the ratio of S-phase podocytes. This result was further verified by knocking down YAP expression using RNA interference. In conclusion, adriamycin induced podocytes to re-enter the cell cycle via upregulation of CDK4 and cyclin D1 expression, which was at least partly mediated by YAP signalling. Re-entry into the cell cycle induced the over-expression of mesenchymal markers in podocytes.

scholarly journals ATAD5 regulates the lifespan of DNA replication factories by modulating PCNA level on the chromatin

2012 ◽  
Vol 200 (1) ◽  
pp. 31-44 ◽  
Author(s):  
Kyoo-young Lee ◽  
Haiqing Fu ◽  
Mirit I. Aladjem ◽  
Kyungjae Myung
Keyword(s):  
Dna Replication ◽  
Molecular Mechanisms ◽  
S Phase ◽  
Nuclear Antigen ◽  
Spatial Regulation ◽  
Replication Factory ◽  
G2 Phase ◽  
Phase Progression ◽  
Temporal And Spatial ◽  
Proliferating Cell

Temporal and spatial regulation of the replication factory is important for efficient DNA replication. However, the underlying molecular mechanisms are not well understood. Here, we report that ATAD5 regulates the lifespan of replication factories. Reduced expression of ATAD5 extended the lifespan of replication factories by retaining proliferating cell nuclear antigen (PCNA) and other replisome proteins on the chromatin during and even after DNA synthesis. This led to an increase of inactive replication factories with an accumulation of replisome proteins. Consequently, the overall replication rate was decreased, which resulted in the delay of S-phase progression. Prevalent detection of PCNA foci in G2 phase cells after ATAD5 depletion suggests that defects in the disassembly of replication factories persist after S phase is complete. ATAD5-mediated regulation of the replication factory and PCNA required an intact ATAD5 ATPase domain. Taken together, our data imply that ATAD5 regulates the cycle of DNA replication factories, probably through its PCNA-unloading activity.

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