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Entry URI http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u16415207i
Entry name Imai Kumiko K et al. 2006 Feb. Plant Cell 18(2):382-96.
Title The A-type cyclin CYCA2;3 is a key regulator of ploidy levels in Arabidopsis endoreduplication.
Authors Aoyama Takashi|Imai Kumiko K|Matsui Minami|Ohashi Yohei|Oka Atsuhiro|Tsuge Tomohiko|Yoshizumi Takeshi
Abstract Plant cells frequently undergo endoreduplication, a process in which chromosomal DNA is successively duplicated in the absence of mitosis. It has been proposed that endoreduplication is regulated at its entry by mitotic cyclin-dependent kinase activity. However, the regulatory mechanisms for its termination remain unclear, although plants tightly control the ploidy level in each cell type. In the process of searching for regulatory factors of endoreduplication, the promoter of an Arabidopsis thaliana cyclin A gene, CYCA2;3, was revealed to be active in developing trichomes during the termination period of endoreduplication as well as in proliferating tissues. Taking advantage of the situation that plants encode highly redundant cyclin A genes, we were able to perform functional dissection of CYCA2;3 using null mutant alleles. Null mutations of CYCA2;3 semidominantly promoted endocycles and increased the ploidy levels achieved in mature organs, but they did not significantly affect the proportion of cells that underwent endoreduplication. Consistent with this result, expression of the CYCA2;3-green fluorescent protein fusion protein restrained endocycles in a dose-dependent manner. Moreover, a mutation in the destruction box of CYCA2;3 stabilized the fusion protein in the nuclei and enhanced the restraint. We conclude that CYCA2;3 negatively regulates endocycles and acts as a key regulator of ploidy levels in Arabidopsis endoreduplication.
Pubmed ID 16415207
Journal The Plant cell
Volume 18
Issue 2
Pages 382-96
Publication date 2006 Feb
Num of phenotype gene 0