Abstract
In plants most organs are composed of cells of various ploidy levels and endoreduplication is a key process in the plant's developmental plan.
To understand the mechanism of endoreduplication, we have set up a unique strategy to screen for endoreduplication mutants systematically. By using flowcytometric analysis and activation tagging mutant lines we isolated several dominant endoreduplication mutants that have increased polyploidy levels. We isolated ilp1-1D as a dominant mutant in which increased polyploidy level enlarge cell volume. ILP1 is a transcriptional repressor and further analysis demonstrated that ILP1 enhance endoreduplication through control of CYCA2 expression transcriptionally.
Currently we identified another dominant mutant showing increased polyploid phenotype from full length cDNA over-expressing lines. Corresponding candidate gene encodes mitochondrial translocon TIM50 and in Drosophila loss of TIM50 caused small body size. We speculated nutrition signal from mitochondria regulates endoreduplication.
Here we show characterization of these mutants and discuss regulation of endoreduplication.
