Volume 29, Issue 6 pp. 300-310
ORIGINAL ARTICLE

The epithelium specific cell cycle regulator 14-3-3sigma is required for preventing entry into mitosis following ultraviolet B

Sandra Vogel

Sandra Vogel

Department of Dermatology and Allergy, Ludwig Maximilian University, Munich, Germany

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Thomas Herzinger

Corresponding Author

Thomas Herzinger

Department of Dermatology and Allergy, Ludwig Maximilian University, Munich, Germany

Correspondence:

Dr Thomas Herzinger, PD, Department of Dermatology and Allergy, Ludwig Maximilian University Munich, Frauenlobstr. 9-11, Munich 80337, Germany.

Tel: +49 89 5160 6054

Fax: +49 89 5160 6132

e-mail: [email protected].

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First published: 27 August 2013
Citations: 4

Conflicts of interest:

None declared.

Summary

Background

Deoxyribonucleic acid damage activates cell cycle checkpoints in order to maintain genomic stability. We assessed the role of different checkpoint genes in response to ultraviolet B irradiation.

Methods

Cell lines expressing a dominant negative mutant of ataxia telangiectasia and Rad3 related (Atr) protein or overexpressing Cdc25A, cells deficient for 14-3-3σ, Nijmegen breakage syndrome (Nbs), or Ataxia telangiectasia mutated (Atm) were treated with ultraviolet B (UVB) and harvested after 12 h, 24 h, or 48 h for analysis by flow cytometry.

Results

Functional loss of Atm, Atr, or Nbs did not result in a significant alteration of the cell cycle profile. Overexpression of Cdc25A led to a delayed arrest at the G1/S transition in response to low doses of UVB. Loss of 14-3-3σ, a negative cell cycle regulator and downstream target of p53, caused a transient arrest at the G2/M boundary.

Conclusions

Loss of 14-3-3σ sensitizes cells to UVB. After a transient cell cycle arrest, 14-3-3σ-deficient cells die by undergoing mitotic catastrophe. Cdc25A overexpression causes a delayed arrest in response to low doses of UVB. After higher doses, Cdc25A is no longer able to overrun the checkpoint. Atm, Atr, or Nbs are not essential for the checkpoint response to UVB, suggesting the existence of redundant signaling pathways.

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