Figure 1. ASI2 Antagonizes Transcriptional Silencing and Prevents DNA Hypermethylation.

(A) Isolation of the asi2-1 mutant. Transgenic over-expression of the sucrose transporter gene SUC2 in Arabidopsis (ecotype Col-0) results in hypersensitivity to exogenous sucrose, as indicated by the short root phenotype in the transgenic plants (Wild type, WT). Dysfunction of ASI2 rescues the sucrose-inhibited root growth phenotype.

(B) RT-qPCR quantification of transgene transcript levels in asi2-1 in comparison to WT plants. Relative ROS1 transcript level was included as an unchanged control.

(C) ASI2 dysfunction causes a loss of kanamycin resistance in the transgenic plants. Treatment with a DNA methylation inhibitor, 5-aza, restores kanamycin resistance in the asi2-1 mutant.

(D) DNA methylation status and MBD7 enrichment at the 35S::SUC2 transgene in WT, asi2-1 and idm3-1 mutants. Shown are screenshots from IGB (Integrative Genome Browser) display of whole genome bisulfite sequencing and ChIP-seq results. Vertical bars on each track indicate DNA methylation levels or MBD7 enrichment at chromatin. Two replicates of ChIP-seq data from MBD7-4xMYC transgenic plants and from WT control plants are displayed.

(E) RT-qPCR analysis of At1TE04710 and At1G26380 in WT and asi2-1 plants.

(F) ASI1 dysfunction compromises heat-induced expression of ONSEN and TSI but not HSP70.

In (B), (E) and (F), RT-qPCR measurements of transcript levels in the asi2-1 mutant are relative to the corresponding values in the WT. All error bars indicate SD, n = 3.

*P<0.01; NS, not significant (two-tailed t-test). See also Figure S1.