The murine Ki-67 cell proliferation antigen accumulates in the nucleolar and heterochromatic regions of interphase cells and at the periphery of the mitotic chromosomes in a process essential for cell cycle progression

1996 ◽  
Vol 109 (1) ◽  
pp. 143-153 ◽  
Author(s):  
M. Starborg ◽  
K. Gell ◽  
E. Brundell ◽  
C. Hoog
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Tandem Repeats ◽  
Sequence Motifs ◽  
Mitotic Chromosomes ◽  
Proliferating Cells ◽  
Ki 67 ◽  
Cycle Progression ◽  
Conserved Sequence ◽  
Interphase Cells

We have isolated the murine homologue of the human Ki-67 antigen. The Ki-67 antigen is used as a marker to assess the proliferative capacity of tumour cells; however, its cellular function is not known. The murine Ki-67 cDNA sequence (TSG126) was found to contain 13 tandem repeats, making up more than half of the total protein size. A comparison of this repetitive sequence block to its human counterpart, which contains 16 consecutive repeat units, revealed several conserved sequence motifs, including one motif frequently observed in proteins interacting with DNA. An antiserum developed against the product of the TSG126 cDNA clone identified a protein with an apparent molecular mass of 360 kDa, mainly expressed in proliferating cells. The TSG126 protein begins to accumulate during the late G1 stage of the cell cycle and is first seen as numerous small granules evenly distributed throughout the nucleus. During the S and the G2 phases, larger foci that overlap with the nucleoli and the heterochromatic regions are formed. At the onset of mitosis the TSG126 protein undergoes a dramatic redistribution process and becomes associated with the surface of the condensed chromosomes. The relative absence of the TSG126 protein from G1 interphase cells strongly argues against a model where the association of the TSG126 protein with mitotic chromosomes merely reflects a mechanism for the symmetrical distribution of nucleolar proteins between daughter cells. Instead, the intracellular distribution of the TSG126 protein during the cell cycle suggests that it could have a chromatin-associated function in both interphase and mitotic cells. Microinjection of anti-TSG126 antibodies into proliferating Swiss-3T3 fibroblasts was found to delay cell cycle progression, indicating that the TSG126 protein has an essential nuclear function.

Deregulated expression of the RanBP1 gene alters cell cycle progression in murine fibroblasts

1997 ◽  
Vol 110 (19) ◽  
pp. 2345-2357 ◽  
Author(s):  
A. Battistoni ◽  
G. Guarguaglini ◽  
F. Degrassi ◽  
C. Pittoggi ◽  
A. Palena ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Cell Cycle Progression ◽  
Protein Import ◽  
Proliferating Cells ◽  
Cycle Progression ◽  
Ran Gtpase ◽  
Genes Encoding ◽  
Active Transcription ◽  
Gtpase Cycle

RanBP1 is a molecular partner of the Ran GTPase, which is implicated in the control of several processes, including DNA replication, mitotic entry and exit, cell cycle progression, nuclear structure, protein import and RNA export. While most genes encoding Ran-interacting partners are constitutively active, transcription of the RanBP1 mRNA is repressed in non proliferating cells, is activated at the G1/S transition in cycling cells and peaks during S phase. We report here that forced expression of the RanBP1 gene disrupts the orderly execution of the cell division cycle at several stages, causing inhibition of DNA replication, defective mitotic exit and failure of chromatin decondensation during the telophase-to-interphase transition in cells that achieve nuclear duplication and chromosome segregation. These results suggest that deregulated RanBP1 activity interferes with the Ran GTPase cycle and prevents the functioning of the Ran signalling system during the cell cycle.

scholarly journals Sequence Motifs in IL-4Rα Mediating Cell-Cycle Progression of Primary Lymphocytes

2005 ◽  
Vol 175 (8) ◽  
pp. 5178-5185 ◽  
Author(s):  
Linda M. Stephenson ◽  
Do-Sim Park ◽  
Ana L. Mora ◽  
Shreevrat Goenka ◽  
Mark Boothby
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Sequence Motifs ◽  
Cycle Progression

scholarly journals Plk4 triggers autonomous de novo centriole biogenesis and maturation

2021 ◽  
Vol 220 (5) ◽  
Author(s):  
Catarina Nabais ◽  
Delphine Pessoa ◽  
Jorge de-Carvalho ◽  
Thomas van Zanten ◽  
Paulo Duarte ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
De Novo ◽  
Cell Types ◽  
Proliferating Cells ◽  
Cycle Progression ◽  
Controlled System ◽  
Pericentriolar Material ◽  
Centriole Assembly ◽  
Critical Components

Centrioles form centrosomes and cilia. In most proliferating cells, centrioles assemble through canonical duplication, which is spatially, temporally, and numerically regulated by the cell cycle and the presence of mature centrioles. However, in certain cell types, centrioles assemble de novo, yet by poorly understood mechanisms. Herein, we established a controlled system to investigate de novo centriole biogenesis, using Drosophila melanogaster egg explants overexpressing Polo-like kinase 4 (Plk4), a trigger for centriole biogenesis. We show that at a high Plk4 concentration, centrioles form de novo, mature, and duplicate, independently of cell cycle progression and of the presence of other centrioles. Plk4 concentration determines the temporal onset of centriole assembly. Moreover, our results suggest that distinct biochemical kinetics regulate de novo and canonical biogenesis. Finally, we investigated which other factors modulate de novo centriole assembly and found that proteins of the pericentriolar material (PCM), and in particular γ-tubulin, promote biogenesis, likely by locally concentrating critical components.

Comparison of cell cycle progression (CCP) score to two IHC markers (PTEN and Ki-67) for predicting outcome in prostate cancer after radical prostatectomy

2018 ◽  
Vol 17 (2) ◽  
pp. e156-e157
Author(s):  
P. Leon Bertrand ◽  
G. Cancel Tassin ◽  
M. Audouin ◽  
S. Drouin ◽  
J. Varinot ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Cycle ◽  
Radical Prostatectomy ◽  
Cell Cycle Progression ◽  
Ki 67 ◽  
Cycle Progression ◽  
Predicting Outcome ◽  
Ihc Markers

scholarly journals Plk4 triggers autonomous de novo centriole biogenesis and maturation

2020 ◽  
Author(s):  
Catarina Nabais ◽  
Delphine Pessoa ◽  
Jorge de-Carvalho ◽  
Thomas van Zanten ◽  
Paulo Duarte ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
De Novo ◽  
Cell Types ◽  
Proliferating Cells ◽  
Cycle Progression ◽  
Controlled System ◽  
Centriole Assembly ◽  
Critical Components ◽  
Kinetics Of

AbstractCentrioles form centrosomes and cilia. In most proliferating cells, centrioles assemble through canonical duplication, which is spatially, temporally and numerically regulated by the cell cycle and the presence of mature centrioles. However, in certain cell-types, centrioles assemble de novo, yet by poorly understood mechanisms. Here, we established a controlled system to investigate de novo centriole biogenesis, using Drosophila melanogaster egg explants overexpressing Polo-like kinase 4 (Plk4), a trigger for centriole biogenesis. We show that at high Plk4 concentration, centrioles form de novo, mature and duplicate, independently of cell cycle progression and of the presence of other centrioles. Plk4 concentration determines the kinetics of centriole assembly. Moreover, our results suggest Plk4 operates in a switch-like manner to control the onset of de novo centriole formation, and that distinct biochemical kinetics regulate de novo and canonical biogenesis. Finally, we investigated which other factors modulate de novo centriole assembly and reveal that proteins of the pericentriolar matrix (PCM) promote biogenesis, likely by locally concentrating critical components.

scholarly journals Ki-67 contributes to normal cell cycle progression and inactive X heterochromatin in p21 checkpoint-proficient human cells

2017 ◽  
Author(s):  
Xiaoming Sun ◽  
Aizhan Bizhanova ◽  
Timothy D. Matheson ◽  
Jun Yu ◽  
Lihua Julie Zhu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Nuclear Lamina ◽  
Cell Types ◽  
S Phase ◽  
Human Cells ◽  
Cell Cycle Distribution ◽  
Ki 67 ◽  
Primary Fibroblast ◽  
Cycle Progression

AbstractKi-67 protein is widely used as a tumor proliferation marker. However, whether Ki-67 affects cell cycle progression has been controversial. Here, we demonstrate that depletion of Ki-67 in human hTERT-RPE1, WI-38, IMR90, hTERT-BJ cell lines and primary fibroblast cells slowed entry into S phase and coordinately downregulated genes related to DNA replication. Some gene expression changes were partially relieved in Ki-67-depleted hTERT-RPE1 cells by co-depletion of the Rb checkpoint protein, but more thorough suppression of the transcriptional and cell cycle defects was observed upon depletion of cell cycle inhibitor p21. Notably, induction of p21 upon depletion of Ki-67 was a consistent hallmark of cell types in which transcription and cell cycle distribution were sensitive to Ki-67; these responses were absent in cells that did not induce p21. Furthermore, upon Ki-67 depletion, a subset of inactive × (Xi) chromosomes in female hTERT-RPE1 cells displayed several features of compromised heterochromatin maintenance, including decreased H3K27me3 and H4K20me1 labeling. These chromatin alterations were limited to Xi chromosomes localized away from the nuclear lamina and were not observed in checkpoint-deficient 293T cells. Altogether, our results indicate that Ki-67 integrates normal S phase progression and Xi heterochromatin maintenance in p21 checkpoint-proficient human cells.

scholarly journals Ki-67 Contributes to Normal Cell Cycle Progression and Inactive X Heterochromatin in p21 Checkpoint-Proficient Human Cells

2017 ◽  
Vol 37 (17) ◽  
Author(s):  
Xiaoming Sun ◽  
Aizhan Bizhanova ◽  
Timothy D. Matheson ◽  
Jun Yu ◽  
Lihua Julie Zhu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Nuclear Lamina ◽  
Cell Types ◽  
S Phase ◽  
Human Cells ◽  
Cell Cycle Distribution ◽  
Ki 67 ◽  
Primary Fibroblast ◽  
Cycle Progression

ABSTRACT The Ki-67 protein is widely used as a tumor proliferation marker. However, whether Ki-67 affects cell cycle progression has been controversial. Here we demonstrate that depletion of Ki-67 in human hTERT-RPE1, WI-38, IMR90, and hTERT-BJ cell lines and primary fibroblast cells slowed entry into S phase and coordinately downregulated genes related to DNA replication. Some gene expression changes were partially relieved in Ki-67-depleted hTERT-RPE1 cells by codepletion of the Rb checkpoint protein, but more thorough suppression of the transcriptional and cell cycle defects was observed upon depletion of the cell cycle inhibitor p21. Notably, induction of p21 upon depletion of Ki-67 was a consistent hallmark of cell types in which transcription and cell cycle distribution were sensitive to Ki-67; these responses were absent in cells that did not induce p21. Furthermore, upon Ki-67 depletion, a subset of inactive X (Xi) chromosomes in female hTERT-RPE1 cells displayed several features of compromised heterochromatin maintenance, including decreased H3K27me3 and H4K20me1 labeling. These chromatin alterations were limited to Xi chromosomes localized away from the nuclear lamina and were not observed in checkpoint-deficient 293T cells. Altogether, our results indicate that Ki-67 integrates normal S-phase progression and Xi heterochromatin maintenance in p21 checkpoint-proficient human cells.

Prognostication by multigene proliferative marker panel compared with Ki-67 in small-intestinal NENs.

2012 ◽  
Vol 30 (4_suppl) ◽  
pp. 242-242
Author(s):  
Ben Lawrence ◽  
Simon Schimmack ◽  
Bernhard Svejda ◽  
Ignat Drozdov ◽  
Daniele Alaimo ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Ki 67 ◽  
Cycle Progression ◽  
Qrt Pcr ◽  
Proliferative Markers ◽  
Cell Cycle Phases ◽  
Proliferative Marker ◽  
Proliferating Cell

242 Background: Ki-67 is the major proliferative marker in clinical use to determine neuroendocrine neoplasm (NEN) prognosis. Ki-67 is unable to predict the outcome of SI-NENs, as the majority have a low (≤2) Ki-67%. Therefore, we aimed to identify a sensitive panel of proliferative markers using qRT-PCR to more accurately define the proliferation of these slow growing tumors. Methods: We identified genes with a mechanistic function in cell cycle progression that were over-expressed in RNA microarrays of SI-NENs (n=8) compared to adjacent normal tissue (n=4) (dCHIP, annotation databases). Timing of marker gene expression (qRT-PCR) in proliferating cell-cycle phases (S, G2, M) was determined in flow-sorted SI-NEN cell lines (KRJ-1, H-STS) after propidium iodide staining. RNA expression of candidate proliferative markers was then investigated using an in vivo model and two independent tumor datasets, and transcript level compared to Ki-67% protein expression (immunohistochemical staining). Results: Twenty genes with a mechanistic role in proliferation were identified and 17 confirmed to be expressed in proliferating cell cycle phases. Each tumor expressed a unique profile of the 17 proliferative markers. Both Ki-67 protein and Ki-67 RNA transcript levels failed to differentiate in vivo SI-NEN models or patient samples despite variable proliferative capacity (e.g., WDNETs versus WDNECs). Although most tumors showed low levels of Ki-67 expression, the tumors expressed high levels of select alternative proliferative markers. Hierarchical clustering provided a novel and clinically meaningful prognostic classification. Conclusions: Proliferation of individual SI-NENs is regulated by unique combinations of multiple genes with a mechanistic role in cell-cycle progression. Regulation of proliferation in SI-NENs is therefore complex and cannot accurately be defined by Ki-67 as a single marker. A panel of proliferative RNA markers has potential to significantly improve prognostication in patients with SI-NENs.

scholarly journals An Overexpression Screen in Drosophila for Genes That Restrict Growth or Cell-Cycle Progression in the Developing Eye

Genetics ◽  
2002 ◽  
Vol 162 (1) ◽  
pp. 229-243 ◽  
Author(s):  
Ai-Sun Kelly Tseng ◽  
Iswar K Hariharan
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Imaginal Disc ◽  
Cell Cycle Progression ◽  
Eye Development ◽  
Gal4 Driver ◽  
Proliferating Cells ◽  
Cycle Progression ◽  
Eye Imaginal Disc ◽  
Doubling Times

AbstractWe screened for genes that, when overexpressed in the proliferating cells of the eye imaginal disc, result in a reduction in the size of the adult eye. After crossing the collection of 2296 EP lines to the ey-GAL4 driver, we identified 46 lines, corresponding to insertions in 32 different loci, that elicited a small eye phenotype. These lines were classified further by testing for an effect in postmitotic cells using the sev-GAL4 driver, by testing for an effect in the wing using en-GAL4, and by testing for the ability of overexpression of cycE to rescue the small eye phenotype. EP lines identified in the screen encompass known regulators of eye development including hh and dpp, known genes that have not been studied previously with respect to eye development, as well as 19 novel ORFs. Lines with insertions near INCENP, elB, and CG11518 were characterized in more detail with respect to changes in growth, cell-cycle phasing, and doubling times that were elicited by overexpression. RNAi-induced phenotypes were also analyzed in SL2 cells. Thus overexpression screens can be combined with RNAi experiments to identify and characterize new regulators of growth and cell proliferation.

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