Abstract
Endoreduplication is a kind of cell cycle that increases nuclear DNA content without cell and nuclear division and is important for plant development.Here we screened mutants showing increased polyploidy from RIKEN Arabidopsis full length cDNA Overexpressor lines (FOX lines) and found that one of the FOX line F07144 showed increase in polyploidy in darkness and the corresponding gene encoded a homologue of mitochondrial translocator subunit TIM50.Tim50 maintains the permeability barrier of mitochondria by closing the translocation pore in presequence regulated manner.We checked sub-cellular localization of F07144 protein using GFP markers and found that this protein was localized in mitochondria, so this F07144 protein can be designated as AtTIM50. GFP fused AtTim50 degrades rapidly and this degradation was stabilized by MG132.Loss of function mutant (SALK059376) showed decrease in polyploidy, reduced plant growth and also low ATP levels than that of wild type plants. Histochemical analysis using GUS reporter gene showed expression pattern in leaves, cotyledons, roots and hypocotyls. Here, we demonstrate that AtTIM50 regulate endoreduplication through cellular ATP-levels.
