Micro-array analysis of gene expression in the Arabidopsis chr11-1 chr17-1 mutant

Chromatin remodeling factors of the Imitation Switch (ISWI) family play important roles in epigenetic regulations of gene expression in yeast and animals, whereas their function in plants remains elusive. Here we report characterization of the Arabidopsis ISWI genes CHR11 and CHR17. Double mutant chr11 chr17 displayed a dramatically reduced plant size with early flowering. In addition, epidermis of the double mutant leaves showed cell characteristics seen only in floral organs. These phenotypes resemble, at least partially, those of the Polycomb mutants curly leaf (clf) and like heterochromatin protein1 (lhp1). Microarray analysis revealed that a number of targets of the Polycomb pathway were derepressed in chr11 chr17 leaves. Furthermore, triple mutants combining chr11 chr17 with clf-29 or lhp1-6 both greatly enhanced clf-29 and lhp1-6 phenotypes, respectively. All these results strongly suggest that the ISWI family genes in Arabidopsis may function in gene silencing via the Polycomb pathway Leaves from 15-day-old seedlings of wild-type Col-0 and chr11-1 chr17-1 were used for RNA preparation.In the experiment data,A refers to Col-0, and B refers to chr11-1 chr17-1.