Three SRA-Domain Methylcytosine-Binding Proteins Cooperate to Maintain Global CpG Methylation and Epigenetic Silencing in Arabidopsis
Figure 7
DNA hypomethylation and transcriptional reactivation in the vim1 vim2 vim3 mutant.
(A) Genic DNA methylation in vim mutants. DNA methylation was analyzed by HpaII-PCR. HpaII-digested genomic DNA was amplified by PCR with primers for the indicated genes. A gene lacking HpaII sites (At4g23560) served as PCR controls. (B) Release of transcriptional silencing of transposons. RT-PCR was carried out using RNA samples from the indicated genotypes. First-strand cDNA synthesis was carried out with or without RT; we did not detect transcripts from the ‘minus RT’ samples. Amplification of GAPC was used to normalize RNA template amounts. (C) DNA methylation in 5S rRNA genes and the 180-bp centromeric repeats (CEN) in vim and met1 mutants. DNA methylation was monitored by DNA gel blot analysis; genomic DNA was digested with HpaII and the blot was hybridized sequentially with radiolabeled probes corresponding to 5S rRNA (left) and the 180-bp centromeric repeats (right). More genomic DNA for the met1-3 mutant was loaded on the gel, so a matched exposure is shown for this sample as a separate box. The numbers shown below the each panel indicate the percentage of hybridization signal present in the bottom band for 5S rRNA genes (denoted by bracket on the left) and in the lower 8 bands for the 180-bp centromere repeats (denoted by bracket on the right).