scholarly journals Perturbation of DNA replication and cell cycle progression by commonly used [3H]thymidine labeling protocols.

1990 ◽  
Vol 10 (4) ◽  
pp. 1584-1592 ◽  
Author(s):  
C A Hoy ◽  
E D Lewis ◽  
R T Schimke
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Cell Cycle Progression ◽  
Specific Activity ◽  
Tritiated Thymidine ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Cesium Chloride ◽  
Cycle Progression ◽  
Ovary Cells

The effect of tritiated thymidine incorporation on DNA replication was studied in Chinese hamster ovary cells. Rapidly eluting (small) DNA from cells labeled with 2 microCi of [3H]thymidine per ml (200 microCi/mmol) for 60 min matured to a large nonelutable size within approximately 2 to 4 h, as measured by the alkaline elution technique. However, DNA from cells exposed to 10 microCi of [3H]thymidine per ml (66 microCi/mmol) was more rapidly eluting initially and did not mature to a nonelutable size during subsequent incubation. Semiconservative DNA replication measured by cesium chloride gradient analysis of bromodeoxyuridine-substituted DNA was also found to be affected by the final specific activity of the [3H]thymidine used in the labeling protocol. Dramatic cell cycle perturbations accompanied these effects on DNA replication, suggesting that labeling protocols commonly used to study DNA metabolism produce aberrant DNA replication and subsequent cell cycle perturbations.

Perturbation of DNA replication and cell cycle progression by commonly used [3H]thymidine labeling protocols

1990 ◽  
Vol 10 (4) ◽  
pp. 1584-1592
Author(s):  
C A Hoy ◽  
E D Lewis ◽  
R T Schimke
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Cell Cycle Progression ◽  
Specific Activity ◽  
Tritiated Thymidine ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Cesium Chloride ◽  
Cycle Progression ◽  
Ovary Cells

The effect of tritiated thymidine incorporation on DNA replication was studied in Chinese hamster ovary cells. Rapidly eluting (small) DNA from cells labeled with 2 microCi of [3H]thymidine per ml (200 microCi/mmol) for 60 min matured to a large nonelutable size within approximately 2 to 4 h, as measured by the alkaline elution technique. However, DNA from cells exposed to 10 microCi of [3H]thymidine per ml (66 microCi/mmol) was more rapidly eluting initially and did not mature to a nonelutable size during subsequent incubation. Semiconservative DNA replication measured by cesium chloride gradient analysis of bromodeoxyuridine-substituted DNA was also found to be affected by the final specific activity of the [3H]thymidine used in the labeling protocol. Dramatic cell cycle perturbations accompanied these effects on DNA replication, suggesting that labeling protocols commonly used to study DNA metabolism produce aberrant DNA replication and subsequent cell cycle perturbations.

Effect of cadmium on cell cycle progression in chinese hamster ovary cells

2004 ◽  
Vol 149 (2-3) ◽  
pp. 125-136 ◽  
Author(s):  
Pei-Ming Yang ◽  
Shu-Jun Chiu ◽  
Kwei-Ann Lin ◽  
Lih-Yuan Lin
Keyword(s):  
Cell Cycle ◽  
Chinese Hamster Ovary ◽  
Cell Cycle Progression ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Cycle Progression ◽  
Ovary Cells

scholarly journals Insulin-Induced Cell Cycle Progression Is Impaired in Chinese Hamster Ovary Cells Overexpressing Insulin Receptor Substrate-3

Endocrinology ◽  
2004 ◽  
Vol 145 (12) ◽  
pp. 5862-5874 ◽  
Author(s):  
Yasushi Kaburagi ◽  
Ryo Yamashita ◽  
Yuzuru Ito ◽  
Hitoshi Okochi ◽  
Ritsuko Yamamoto-Honda ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Insulin Receptor ◽  
Cyclin D1 ◽  
Cell Cycle Progression ◽  
Glycogen Synthase ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Glycogen Synthase Kinase 3 ◽  
Cycle Progression ◽  
Ovary Cells

Abstract To analyze the roles of insulin receptor substrate (IRS) proteins in insulin-stimulated cell cycle progression, we examined the functions of rat IRS-1 and IRS-3 in Chinese hamster ovary cells overexpressing the human insulin receptor. In this type of cell overexpressing IRS-1 or IRS-3, we showed that: 1) overexpression of IRS-3, but not IRS-1, suppressed the G1/S transition induced by insulin; 2) IRS-3 was more preferentially localized to the nucleus than IRS-1; 3) phosphorylation of glycogen synthase kinase 3 and MAPK/ERK was unaffected by IRS-3 overexpression, whereas that of protein kinase B was enhanced by either IRS; 4) overexpressed IRS-3 suppressed cyclin D1 expression in response to insulin; 5) among the signaling molecules regulating cyclin D1 expression, activation of the small G protein Ral was unchanged, whereas insulin-induced gene expression of c-myc, a critical component for growth control and cell cycle progression, was suppressed by overexpressed IRS-3; and 6) insulin-induced expression of p21, a cyclin-dependent kinase inhibitor, was decreased by overexpressed IRS-3. These findings imply that: 1) IRS-3 may play a unique role in mitogenesis by inhibiting insulin-stimulated cell cycle progression via a decrease in cyclin D1 and p21 expressions as well as suppression of c-myc mRNA induction in a manner independent of the activation of MAPK, protein kinase B, glycogen synthase kinase 3 and Ral; and 2) the interaction of IRS-3 with nuclear proteins may be involved in this process.

scholarly journals Regulation of Cell Division in Bacteria by Monitoring Genome Integrity and DNA Replication Status

2019 ◽  
Vol 202 (2) ◽  
Author(s):  
Peter E. Burby ◽  
Lyle A. Simmons
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Division ◽  
Dna Replication ◽  
Cell Cycle Progression ◽  
Genome Instability ◽  
Sos Response ◽  
Bacterial Cells ◽  
Cycle Progression ◽  
Content Type

ABSTRACT All organisms regulate cell cycle progression by coordinating cell division with DNA replication status. In eukaryotes, DNA damage or problems with replication fork progression induce the DNA damage response (DDR), causing cyclin-dependent kinases to remain active, preventing further cell cycle progression until replication and repair are complete. In bacteria, cell division is coordinated with chromosome segregation, preventing cell division ring formation over the nucleoid in a process termed nucleoid occlusion. In addition to nucleoid occlusion, bacteria induce the SOS response after replication forks encounter DNA damage or impediments that slow or block their progression. During SOS induction, Escherichia coli expresses a cytoplasmic protein, SulA, that inhibits cell division by directly binding FtsZ. After the SOS response is turned off, SulA is degraded by Lon protease, allowing for cell division to resume. Recently, it has become clear that SulA is restricted to bacteria closely related to E. coli and that most bacteria enforce the DNA damage checkpoint by expressing a small integral membrane protein. Resumption of cell division is then mediated by membrane-bound proteases that cleave the cell division inhibitor. Further, many bacterial cells have mechanisms to inhibit cell division that are regulated independently from the canonical LexA-mediated SOS response. In this review, we discuss several pathways used by bacteria to prevent cell division from occurring when genome instability is detected or before the chromosome has been fully replicated and segregated.

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