scholarly journals Role of inhibitory CDC2 phosphorylation in radiation-induced G2 arrest in human cells.

1996 ◽  
Vol 134 (4) ◽  
pp. 963-970 ◽  
Author(s):  
P Jin ◽  
Y Gu ◽  
D O Morgan
Keyword(s):  
Dna Damage ◽  
Chromatin Condensation ◽  
S Phase ◽  
Human Cells ◽  
G2 Arrest ◽  
Hela Cell Lines ◽  
Radiation Induced ◽  
G2 Delay ◽  
In Cells

The activity of the mitosis-promoting kinase CDC2-cyclin B is normally suppressed in S phase and G2 by inhibitory phosphorylation at Thr14 and Tyr15. This work explores the possibility that these phosphorylations are responsible for the G2 arrest that occurs in human cells after DNA damage. HeLa cell lines were established in which CDC2AF, a mutant that cannot be phosphorylated at Thr14 and Tyr15, was expressed from a tetracycline-repressible promoter. Expression of CDC2AF did not induce mitotic events in cells arrested at the beginning of S phase with DNA synthesis inhibitors, but induced low levels of premature chromatin condensation in cells progressing through S phase and G2. Expression of CDC2AF greatly reduced the G2 delay that resulted when cells were X-irradiated in S phase. However, a significant G2 delay was still observed and was accompanied by high CDC2-associated kinase activity. Expression of wild-type CDC2, or the related kinase CDK2AF, had no effect on the radiation-induced delay. Thus, inhibitory phosphorylation of CDC2, as well as additional undefined mechanisms, delay mitosis after DNA damage.

Influence of metallothionein-1 localization on its function

2001 ◽  
Vol 355 (2) ◽  
pp. 473-479 ◽  
Author(s):  
Marilyne LEVADOUX-MARTIN ◽  
John E. HESKETH ◽  
John H. BEATTIE ◽  
Heather M. WALLACE
Keyword(s):  
Dna Damage ◽  
Uv Light ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Protective Role ◽  
S Phase ◽  
Coding Region ◽  
Ovary Cells ◽  
In Cells

Metallothioneins (MTs) have a major role to play in metal metabolism, and may also protect DNA against oxidative damage. MT protein has been found localized in the nucleus during S-phase. The mRNA encoding the MT-1 isoform has a perinuclear localization, and is associated with the cytoskeleton; this targeting, due to signals within the 3′-untranslated region (3′-UTR), facilitates nuclear localization of MT-1 during S-phase [Levadoux, Mahon, Beattie, Wallace and Hesketh (1999) J. Biol. Chem. 274, 34961-34966]. Using cells transfected with MT gene constructs differing in their 3′-UTRs, the role of MT protein in the nucleus has been studied. Chinese hamster ovary cells were transfected with either the full MT gene (MTMT cells) or with the MT 5′-UTR and coding region linked to the 3′-UTR of glutathione peroxidase (MTGSH cells). Cell survival following exposure to oxidative stress and chemical agents was higher in cells expressing the native MT gene than in cells where MT localization was disrupted, or in untransfected cells. Also, MTMT cells showed less DNA damage than MTGSH cells in response to either hydrogen peroxide or mutagen. After exposure to UV light or mutagen, MTMT cells showed less apoptosis than MTGSH cells, as assessed by DNA fragmentation and flow cytometry. The data indicate that the perinuclear localization of MT mRNA is important for the function of MT in a protective role against DNA damage and apoptosis induced by external stress.

scholarly journals Human DNA Polymerase η Is Required for Common Fragile Site Stability during Unperturbed DNA Replication

2009 ◽  
Vol 29 (12) ◽  
pp. 3344-3354 ◽  
Author(s):  
Laurie Rey ◽  
Julia M. Sidorova ◽  
Nadine Puget ◽  
François Boudsocq ◽  
Denis S. F. Biard ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Polymerase ◽  
Genome Stability ◽  
Fragile Site ◽  
S Phase ◽  
Human Cells ◽  
Common Fragile Site ◽  
Exogenous Dna ◽  
Human Dna

ABSTRACT Human DNA polymerase η (Pol η) modulates susceptibility to skin cancer by promoting translesion DNA synthesis (TLS) past sunlight-induced cyclobutane pyrimidine dimers. Despite its well-established role in TLS synthesis, the role of Pol η in maintaining genome stability in the absence of external DNA damage has not been well explored. We show here that short hairpin RNA-mediated depletion of Pol η from undamaged human cells affects cell cycle progression and the rate of cell proliferation and results in increased spontaneous chromosome breaks and common fragile site expression with the activation of ATM-mediated DNA damage checkpoint signaling. These phenotypes were also observed in association with modified replication factory dynamics during S phase. In contrast to that seen in Pol η-depleted cells, none of these cellular or karyotypic defects were observed in cells depleted for Pol ι, the closest relative of Pol η. Our results identify a new role for Pol η in maintaining genomic stability during unperturbed S phase and challenge the idea that the sole functional role of Pol η in human cells is in TLS DNA damage tolerance and/or repair pathways following exogenous DNA damage.

scholarly journals The role of CSA in the response to oxidative DNA damage in human cells

Oncogene ◽  
2007 ◽  
Vol 26 (30) ◽  
pp. 4336-4343 ◽  
Author(s):  
M D'Errico ◽  
E Parlanti ◽  
M Teson ◽  
P Degan ◽  
T Lemma ◽  
...  
Keyword(s):  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Human Cells

scholarly journals The Total Amount of DNA Damage Determines Ultraviolet-radiation-induced Cytotoxicity After Uniformor Localized Irradiation of Human Cells

2002 ◽  
Vol 119 (5) ◽  
pp. 1177-1182 ◽  
Author(s):  
Kyoko Imoto ◽  
Nobuhiko Kobayashi ◽  
Sachiko Katsumi ◽  
Yoko Nishiwaki ◽  
Taka-aki Iwamoto ◽  
...  
Keyword(s):  
Dna Damage ◽  
Ultraviolet Radiation ◽  
Human Cells ◽  
Radiation Induced
Sign in / Sign up

Export Citation Format

Share Document