Absence of a synergistic effect between moderate-power radio-frequency electromagnetic radiation and adriamycin on cell-cycle progression and sister-chromatid exchange

Faithful genome transmission in dividing cells requires that the two copies of each chromosome’s DNA package into separate, but physically linked, sister chromatids. The linkage between sister chromatids is mediated by cohesin, yet where sister chromatids are linked and how they resolve during cell cycle progression has remained unclear. Here, we investigated sister chromatid organization in live human cells using dCas9-mEGFP labelling of endogenous genomic loci. We detected substantial sister locus separation during G2 phase, irrespective of the proximity to cohesin enrichment sites. Almost all sister loci separated within a few hours after their respective replication, and then rapidly equilibrated their average distances within dynamic chromatin polymers. Our findings explain why the topology of sister chromatid resolution in G2 largely reflects the DNA replication program. Further, these data suggest that cohesin enrichment sites are not persistent cohesive sites in human cells. Rather, cohesion might occur at variable genomic positions within the cell population.

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Dynamics of sister chromatid resolution during cell cycle progression

The Journal of Cell Biology ◽

10.1083/jcb.201801157 ◽

2018 ◽

Vol 217 (6) ◽

pp. 1985-2004 ◽

Cited By ~ 20

Author(s):

Rugile Stanyte ◽

Johannes Nuebler ◽

Claudia Blaukopf ◽

Rudolf Hoefler ◽

Roman Stocsits ◽

...

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Sister Chromatid ◽

Cell Cycle Progression ◽

Human Cells ◽

Cycle Progression ◽

Sister Chromatids ◽

Dividing Cells ◽

G2 Phase ◽

Almost All

Faithful genome transmission in dividing cells requires that the two copies of each chromosome’s DNA package into separate but physically linked sister chromatids. The linkage between sister chromatids is mediated by cohesin, yet where sister chromatids are linked and how they resolve during cell cycle progression has remained unclear. In this study, we investigated sister chromatid organization in live human cells using dCas9-mEGFP labeling of endogenous genomic loci. We detected substantial sister locus separation during G2 phase irrespective of the proximity to cohesin enrichment sites. Almost all sister loci separated within a few hours after their respective replication and then rapidly equilibrated their average distances within dynamic chromatin polymers. Our findings explain why the topology of sister chromatid resolution in G2 largely reflects the DNA replication program. Furthermore, these data suggest that cohesin enrichment sites are not persistent cohesive sites in human cells. Rather, cohesion might occur at variable genomic positions within the cell population.

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Erythrocytes modulate cell cycle progression but not the baseline frequency of sister chromatid exchanges in pig lymphocytes

Brazilian Journal of Genetics ◽

10.1590/s0100-84551997000300007 ◽

1997 ◽

Vol 20 (3) ◽

pp. 397-403 ◽

Cited By ~ 1

Author(s):

Miguel A. Reigosa ◽

Sonia Soloneski ◽

Carlos F. Garcia ◽

Marcelo L. Larramendy

Keyword(s):

Cell Cycle ◽

Sister Chromatid ◽

Cell Cycle Progression ◽

Sister Chromatid Exchanges ◽

Dependent Manner ◽

Cycle Progression ◽

Baseline Frequency ◽

Chromatid Exchanges ◽

Human Rbcs

The effect of co-culturing varying concentrations of pig and human red blood cells (RBCs) on the baseline frequency of sister chromatid exchanges (SCEs) and cell-cycle progression in pig plasma (PLCs) and whole blood leukocyte cultures (WBCs) was studied. No variation in SCE frequency was observed between pig control WBC and PLC. Addition of pig and human RBCs to pig PLCs did not modify the baseline frequency of SCEs. On the other hand, cell proliferation was slower in PLCs than in WBCs. The addition of pig or human RBCs to PLCs accelerated the cell-cycle progression of pig lymphocytes. When RBCs were added to PLCs the concentration and time sequence of RBC incorporation affected the cell-cycle progression of swine lymphocytes. When doses of pig or human RBCs equivalent to those present in WBCs were added immediately after PLC stimulation, the cell-cycle kinetics were similar to those of WBCs. Shorter co-incubation periods or a reduction in the dose of RBCs made cell-cycle progression intermediate between PLC and WBC values. Thus, pig and human RBCs modulated the in vitro cell-cycle progression of pig lymphocytes in a time- and dose-dependent manner, and the low baseline frequency of SCEs of pig lymphocytes is independent of the presence or absence of erythrocytes in culture

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