Abstract
Repetitive elements such as transposons dispersed in genome are stably silenced by DNA cytosine methylation. On the other hand, genes are generally excluded from the DNA methylation, suggesting that cells might have mechanisms that distinguish genes and repetitive elements and deposit the characteristic epigenetic modifications.
To explore the underlying mechanisms, we are studying epigenetic factors in Arabidopsis, which are required for proper DNA methylation patterns in the genome. DNA methylation at repetitive elements are maintained by the chromatin remodeling factor DDM1 (DECREASE IN DNA METHYLATION1). In contrast, genes are protected from DNA methylation by the jmj-C type histone H3 Lys 9 demethylase IBM1 (INCREASE IN BONSAI METHYLATION1).
Interestingly, ddm1 ibm1 double mutants exhibit severe growth defects and complete sterility, which are never observed in the single mutants. This suggests that there might be a functional relationship between DDM1 and IBM1. We are currently dissecting the mutant phenotypes and will present the latest results in this meeting.
