A Change in the CACTA Transposon Mobility in Arabidopsis thaliana.

Abstract

Arabidopsis thaliana have CACTA transposons in their genomes. We previously reported that CACTAs are mobilized by ddm1 mutant. Moreover, we described that CACTA activated by the ddm1 mutation remains mobile in the DDM1 wild-type background. These findings indicated that DNA methylation works as a heritable epigenetic mark to silence CACTA transposon. In this study, we examined the developmental timing of the CACTA mobilization. We estimated CACTA1 transposition frequency by PCR. PCR analysis showed that the first ddm1 homozygous generation plants contained less genome copies that had the excised original CACTA1 locus than the next generation did. Currently, we are analyzing transgenic plant with 35S-dCACTA-GUS construct for histological evidence of CACTA excision. We will discuss the mechanism of the activation of the CACTA transposition during the developmental process.