Molecular and cellular aspects of programmed cell death in response to genotoxics in plants
Language English
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Author : Smetana, Ondrej
Date : 30-09-2010

Research director(s) : Chaboute, Marie-Edith - Opatrny, Zdenek


Institution : Université de Strasbourg
Doctoral school : École doctorale Sciences de la vie et de la santé (Strasbourg ; 2000-....)
 
Discipline : Sciences de la vie et de la santé
Classification : Botanical Sciences

Keyword(s) : programmed cell death ; dna damge ; cell cycle checkpoint ; E2F ; by-2 cells ; endoreduplication ; Arabidopsis ; ATM and ATR kinases
Keyword(s) :
  • Arabis thaliana - Thèses et écrits académiques
  • Apoptose - Thèses et écrits académiques
Abstract : Plants are continuously exposed to different endogenous and exogenous stresses and thus, compared to animals, they had to evolve specific defense mechanisms due to their sessile life. One of these stresses is DNA damage,which must be precisely repaired to avoid the generation of harmful DNA mutation which could, in extreme cases, lead to programmed cell death (PCD). DNA damage response is conserved among Eukaryotes, thus some regulators, such as ATM, ATR or E2F, have been identified in both,animals and plants. The kinase ATM is essential for the response to DNA double strand breaks (DBSs) and, in mammals, modulates the activity of p53 and E2F transcriptional factors involved in PCD induction. Compared to p53,E2F members were identified also in plants,but their role in PCD regulation remains unknown. Using BY-2 cells and Arabidopsis, we demonstrated that bleomycin (BLM a DBS inducer) treatment led to PCD mediated by vacuolar collapse but via different signaling pathways according to BLM concentrations. At high BLM doses, PCD induction was controlled by ATM, but at low BLM doses cell death induction was ATM-independent.In Arabidopsis root, PCD occurred mainly in the meristem leading to differentiation and endoreduplication of the root tip cells mediated by the modification of auxin fluxes.In non-differentiated BY-2 cells,high doses of BLM induced PCD which was not cell cycle-regulated and which was inhibited by E2F overexpression. At low doses,BLM specifically induced cell death at the G2/M cell cycle checkpoint which was together with PCD bypassed by E2F overexpresion. Taken our results together, we demonstrate some plant specificities of PCD regulation in response to DBSs.
 
Content type : Text
 
Repository : Local resource
Identifier : ecrin-ori-304311
Document type : TEF