Restoration of G1 chemo/radioresistance and double-strand-break repair proficiency by wild-type but not endonuclease-deficient Artemis
| Autor: | Lawrence F. Povirk, Susovan Mohapatra, Steven M. Yannone, Misako Kawahara, Imran S. Khan |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
DNA Repair
Cell Survival DNA repair Genome Integrity Repair and Replication Promyelocytic Leukemia Protein Biology medicine.disease_cause Radiation Tolerance Bleomycin 03 medical and health sciences Promyelocytic leukemia protein Endonuclease 0302 clinical medicine Zinostatin DCLRE1C Gene Radioresistance Genetics medicine Humans DNA Breaks Double-Stranded 030304 developmental biology 0303 health sciences Mutation Endodeoxyribonucleases Tumor Suppressor Proteins G1 Phase Wild type Nuclear Proteins Endonucleases Molecular biology Double Strand Break Repair DNA-Binding Proteins 030220 oncology & carcinogenesis biology.protein Transcription Factors |
| Zdroj: | Nucleic Acids Research |
| ISSN: | 1362-4962 0305-1048 |
| Popis: | Deficiency in Artemis is associated with lack of V(D)J recombination, sensitivity to radiation and radiomimetic drugs, and failure to repair a subset of DNA double-strand breaks (DSBs). Artemis harbors an endonuclease activity that trims both 5'- and 3'-ends of DSBs. To examine whether endonucleolytic trimming of terminally blocked DSBs by Artemis is a biologically relevant function, Artemis-deficient fibroblasts were stably complemented with either wild-type Artemis or an endonuclease-deficient D165N mutant. Wild-type Artemis completely restored resistance to γ-rays, bleomycin and neocarzinostatin, and also restored DSB-repair proficiency in G0/G1 phase as measured by pulsed-field gel electrophoresis and repair focus resolution. In contrast, cells expressing the D165N mutant, even at very high levels, remained as chemo/radiosensitive and repair deficient as the parental cells, as evidenced by persistent γ-H2AX, 53BP1 and Mre11 foci that slowly increased in size and ultimately became juxtaposed with promyelocytic leukemia protein nuclear bodies. In normal fibroblasts, overexpression of wild-type Artemis increased radioresistance, while D165N overexpression conferred partial repair deficiency following high-dose radiation. Restoration of chemo/radioresistance by wild-type, but not D165N Artemis suggests that the lack of endonucleolytic trimming of DNA ends is the principal cause of sensitivity to double-strand cleaving agents in Artemis-deficient cells. |
| Databáze: | OpenAIRE |
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