Fig. 1

Schematic model of MUC1 gene regulation through epigenetic modifications. Open chromatin is characterized by an unmethylated status of the MUC1 promoter and histones with acetylated H3-K9. This may allow assembly of transcription factors and transcription by RNA polymerase. DNA methylation and histone deacetylation result in condensation of chromatin into a compact state that is inaccessible to transcription factors. The MUC1 gene can also be posttranscriptionally regulated by miRNAs (miR-125b, miR-145, or miR-1226) that target the 3′-UTR of MUC1 mRNA and cause mRNA degradation or translational repression