The G2 checkpoint activated by DNA damage does not prevent genome instability in plant cells
Root growth, G2 length, and the frequency of aberrant mitoses and apoptotic nuclei were recorded after a single X-ray irradiation, ranging from 2.5 to 40 Gy, in Allium cepa L. root meristematic cells. After 72 h of recovery, root growth was reduced in a dose-dependent manner from 10 to 40 Gy, but no...
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| Format: | Article |
| Language: | English |
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BMC
2006-01-01
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| Series: | Biological Research |
| Subjects: | |
| Online Access: | http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000200015 |
| _version_ | 1818232021552463872 |
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| author | JESÚS A CARBALLO JUANA PINCHEIRA CONSUELO DE LA TORRE |
| author_facet | JESÚS A CARBALLO JUANA PINCHEIRA CONSUELO DE LA TORRE |
| author_sort | JESÚS A CARBALLO |
| collection | DOAJ |
| description | Root growth, G2 length, and the frequency of aberrant mitoses and apoptotic nuclei were recorded after a single X-ray irradiation, ranging from 2.5 to 40 Gy, in Allium cepa L. root meristematic cells. After 72 h of recovery, root growth was reduced in a dose-dependent manner from 10 to 40 Gy, but not at 2.5 or 5 Gy doses. Flow cytometry plus TUNEL (TdT-mediated dUTP nick end labeling) showed that activation of apoptosis occurred only after 20 and 40 Gy of X-rays. Nevertheless, irrespective of the radiation dose, conventional flow cytometry showed that cells accumulated in G2 (4C DNA content). Simultaneously, the mitotic index fell, though a mitotic wave appeared later. Cell accumulation in G2 was transient and partially reversed by caffeine, thus it was checkpoint-dependent. Strikingly, the additional G2 time provided by this checkpoint was never long enough to complete DNA repair. Then, in all cases, some G2 cells with still-unrepaired DNA underwent checkpoint adaptation, i.e., they entered into the late mitotic wave with chromatid breaks. These cells and those produced by the breakage of chromosomal bridges in anaphase will reach the G1 of the next cell cycle unrepaired, ensuring the appearance of genome instability |
| first_indexed | 2024-12-12T10:59:40Z |
| format | Article |
| id | doaj.art-85844ef8a502408293577c31b993848f |
| institution | Directory Open Access Journal |
| issn | 0716-9760 0717-6287 |
| language | English |
| last_indexed | 2024-12-12T10:59:40Z |
| publishDate | 2006-01-01 |
| publisher | BMC |
| record_format | Article |
| series | Biological Research |
| spelling | doaj.art-85844ef8a502408293577c31b993848f2022-12-22T00:26:35ZengBMCBiological Research0716-97600717-62872006-01-01392331340The G2 checkpoint activated by DNA damage does not prevent genome instability in plant cellsJESÚS A CARBALLOJUANA PINCHEIRACONSUELO DE LA TORRERoot growth, G2 length, and the frequency of aberrant mitoses and apoptotic nuclei were recorded after a single X-ray irradiation, ranging from 2.5 to 40 Gy, in Allium cepa L. root meristematic cells. After 72 h of recovery, root growth was reduced in a dose-dependent manner from 10 to 40 Gy, but not at 2.5 or 5 Gy doses. Flow cytometry plus TUNEL (TdT-mediated dUTP nick end labeling) showed that activation of apoptosis occurred only after 20 and 40 Gy of X-rays. Nevertheless, irrespective of the radiation dose, conventional flow cytometry showed that cells accumulated in G2 (4C DNA content). Simultaneously, the mitotic index fell, though a mitotic wave appeared later. Cell accumulation in G2 was transient and partially reversed by caffeine, thus it was checkpoint-dependent. Strikingly, the additional G2 time provided by this checkpoint was never long enough to complete DNA repair. Then, in all cases, some G2 cells with still-unrepaired DNA underwent checkpoint adaptation, i.e., they entered into the late mitotic wave with chromatid breaks. These cells and those produced by the breakage of chromosomal bridges in anaphase will reach the G1 of the next cell cycle unrepaired, ensuring the appearance of genome instabilityhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000200015apoptosischeckpoint adaptationG2 DNA damage checkpointgenome instabilityX-rays |
| spellingShingle | JESÚS A CARBALLO JUANA PINCHEIRA CONSUELO DE LA TORRE The G2 checkpoint activated by DNA damage does not prevent genome instability in plant cells Biological Research apoptosis checkpoint adaptation G2 DNA damage checkpoint genome instability X-rays |
| title | The G2 checkpoint activated by DNA damage does not prevent genome instability in plant cells |
| title_full | The G2 checkpoint activated by DNA damage does not prevent genome instability in plant cells |
| title_fullStr | The G2 checkpoint activated by DNA damage does not prevent genome instability in plant cells |
| title_full_unstemmed | The G2 checkpoint activated by DNA damage does not prevent genome instability in plant cells |
| title_short | The G2 checkpoint activated by DNA damage does not prevent genome instability in plant cells |
| title_sort | g2 checkpoint activated by dna damage does not prevent genome instability in plant cells |
| topic | apoptosis checkpoint adaptation G2 DNA damage checkpoint genome instability X-rays |
| url | http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000200015 |
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