Light-dependent polyploidy control by a CUE protein variant in Arabidopsis

• Published in: Plant molecular biology 2006-07, Vol.61 (4-5), p.817-828
• Main Authors: Tsumoto, Y, Yoshizumi, T, Kuroda, H, Kawashima, M, Ichikawa, T, Nakazawa, M, Yamamoto, N, Matsui, M
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Arabidopsis; Arabidopsis - cytology; Arabidopsis - genetics; Arabidopsis - radiation effects; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Cell cycle; Gene Expression; Genes, Dominant - genetics; Light; Mitosis; Mutation; Phenotype; Polyploidy; Protein Structure, Tertiary; Seedlings; Transgenic plants
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/s11103-006-0053-4

Endoreduplication is a special cell cycle that increases ploidy without cell and nuclear division. In plants endoreduplication is essential for development. We isolated a dominant Arabidopsis mutant from activation tagging lines that had increased polyploidy in darkness. This mutant, ipd1-1D (increased polyploidy level in darkness 1-1D), shows longer hypocotyls and increased ploidy levels only in dark-grown seedlings. The corresponding gene encodes a protein that contains a CUE domain variant. IPD1 is specifically expressed in mitotically dividing cells. Furthermore we show that blue and far-red light can suppress the ploidy increase in ipd1-1D and also suppress the reporter expression in IPD1-promoter β-glucuronidase transgenic plants. These results suggest that IPD1 regulates the endocycle leading to hypocotyl elongation and this function is controlled by blue and far-red light.