Abstract
Endoreduplication is a special cell cycle containing successive DNA replication in the absence of mitosis. But, little is known about the molecular mechanism of endreduplication.
To reveal this mechanism, we analyzed a Arabidopsis mutant, increased level of polyploidy4-D (ilp4-D), which was isolated from activation tagging lines. ilp4-D showed increased polyploidy in the seedlings. ILP4 gene encodes a protein that contains a kinase domain. Histochemical analysis using a ILP4promoter-GUS reporter gene showed ILP4 was expressed in part of root, cotyledon and hypocotyls, suggesting ILP4 expression has cell specificity. ILP4 protein localized in nuclear analyzed with GFP fusion protein.
T-DNA insertion lines of ILP4 were did not show any obvious phenotype. ILP4 and ILP4L1 (ILP4 homologue) double mutant showed slightly decreased polyploidy level in dark seedlings.
Overexpression of ILP4 gene which was deleted kinase domain led to increase polyploidy level. These results suggested ILP4 kinase domain is not related to endocycle.
