DNA methylation in liver diseases

Figure 1 DNA methylation pattern in different parts of the genomes. The normal conditions are presented in the left column and aberrant conditions are shown on the right. The black dots represent methylated CpG sites and the white circles represent unmethylated CpG sites. A: In normal cells, CpG islands (CGI) in transcriptional start site (TSS) usually remain unmethylated, allowing transcription. Aberrant methylation often links to long-term stabilization of transcriptional silencing and loss of gene function both physically and pathologically; B: In normal cells, gene bodies are CpG-poor and extensively methylated, increasing elongation efficacy. Aberrant demethylation of gene bodies may facilitates spurious initiations of transcription; C: In normal cells, repetitive sequences of genome are highly methylated, preventing chromosomal instability or gene disruption. Aberrant demethylation of repetitive sequences may reactivate endoparasitic sequences.