p53-Independent checkpoint controls in a plant cell model

Allium cepa L. meristems were used as a plant model to study the p53-independent control of S and G2 phases by checkpoint pathways, in eukaryotic cells. Checkpoint blocks were induced at early and mid S by hydroxyurea. After their spontaneous override, cells became accumulated in G2-prophase, giving...

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Main Authors: HELVIA R PELAYO, JUANA PINCHEIRA, JUAN F GIMÉNEZ-ABIÁN, DUNCAN J CLARKE, CONSUELO DE LA TORRE
Format: Article
Language:English
Published: BMC 2003-01-01
Series:Biological Research
Subjects:
Online Access:http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602003000300009
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spelling doaj-69606b0cbd134f3eb2763354ccacdfe02020-11-25T00:47:01ZengBMCBiological Research0716-97600717-62872003-01-01363-4381388p53-Independent checkpoint controls in a plant cell modelHELVIA R PELAYOJUANA PINCHEIRAJUAN F GIMÉNEZ-ABIÁNDUNCAN J CLARKECONSUELO DE LA TORREAllium cepa L. meristems were used as a plant model to study the p53-independent control of S and G2 phases by checkpoint pathways, in eukaryotic cells. Checkpoint blocks were induced at early and mid S by hydroxyurea. After their spontaneous override, cells became accumulated in G2-prophase, giving rise later on to a delayed mitotic wave. Cell growth was maintained during the checkpoint blocks, as the delayed mitoses were larger in size than the control ones. Under continuous hydroxyurea treatment, the delayed mitotic was formed by two subpopulations: normal mitoses corresponding to cells having properly recovered from the checkpoint block, and abnormal ones resulting from checkpoint adaptation. These latter cells displayed broken chromatids as they had unduly overriden the G2 checkpoint block, without completing DNA repair. The frequency of the checkpoint-adapted mitoses increased with the hydroxyurea concentration from 0.25 to 1.0 mM. However, from 1 mM hydroxyurea upwards, some of the cells lost their competence for checkpoint adaptation. Therefore, the dose of a genotoxic agent that still allows G2 checkpoint adaptation should always be applied in order to get rid of uncontrolled proliferating cells. This is specially suitable for cells lacking a functional p53 proteinhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602003000300009Checkpoint adaptationHydroxyureaS and G2 checkpointsp53-independent checkpointsAllium cepa L. meristems
collection DOAJ
language English
format Article
sources DOAJ
author HELVIA R PELAYO
JUANA PINCHEIRA
JUAN F GIMÉNEZ-ABIÁN
DUNCAN J CLARKE
CONSUELO DE LA TORRE
spellingShingle HELVIA R PELAYO
JUANA PINCHEIRA
JUAN F GIMÉNEZ-ABIÁN
DUNCAN J CLARKE
CONSUELO DE LA TORRE
p53-Independent checkpoint controls in a plant cell model
Biological Research
Checkpoint adaptation
Hydroxyurea
S and G2 checkpoints
p53-independent checkpoints
Allium cepa L. meristems
author_facet HELVIA R PELAYO
JUANA PINCHEIRA
JUAN F GIMÉNEZ-ABIÁN
DUNCAN J CLARKE
CONSUELO DE LA TORRE
author_sort HELVIA R PELAYO
title p53-Independent checkpoint controls in a plant cell model
title_short p53-Independent checkpoint controls in a plant cell model
title_full p53-Independent checkpoint controls in a plant cell model
title_fullStr p53-Independent checkpoint controls in a plant cell model
title_full_unstemmed p53-Independent checkpoint controls in a plant cell model
title_sort p53-independent checkpoint controls in a plant cell model
publisher BMC
series Biological Research
issn 0716-9760
0717-6287
publishDate 2003-01-01
description Allium cepa L. meristems were used as a plant model to study the p53-independent control of S and G2 phases by checkpoint pathways, in eukaryotic cells. Checkpoint blocks were induced at early and mid S by hydroxyurea. After their spontaneous override, cells became accumulated in G2-prophase, giving rise later on to a delayed mitotic wave. Cell growth was maintained during the checkpoint blocks, as the delayed mitoses were larger in size than the control ones. Under continuous hydroxyurea treatment, the delayed mitotic was formed by two subpopulations: normal mitoses corresponding to cells having properly recovered from the checkpoint block, and abnormal ones resulting from checkpoint adaptation. These latter cells displayed broken chromatids as they had unduly overriden the G2 checkpoint block, without completing DNA repair. The frequency of the checkpoint-adapted mitoses increased with the hydroxyurea concentration from 0.25 to 1.0 mM. However, from 1 mM hydroxyurea upwards, some of the cells lost their competence for checkpoint adaptation. Therefore, the dose of a genotoxic agent that still allows G2 checkpoint adaptation should always be applied in order to get rid of uncontrolled proliferating cells. This is specially suitable for cells lacking a functional p53 protein
topic Checkpoint adaptation
Hydroxyurea
S and G2 checkpoints
p53-independent checkpoints
Allium cepa L. meristems
url http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602003000300009
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AT juanapincheira p53independentcheckpointcontrolsinaplantcellmodel
AT juanfgimenezabian p53independentcheckpointcontrolsinaplantcellmodel
AT duncanjclarke p53independentcheckpointcontrolsinaplantcellmodel
AT consuelodelatorre p53independentcheckpointcontrolsinaplantcellmodel
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