A model for vigilin-induced silencing. (A) In the nucleus, vigilin binds to hyperedited RNA or other unstructured RNAs that reside in heterochromatic regions and recruits a protein complex including the Ku70/Ku86 heterodimer, RHA, and the histone methyltransferase, SUV39H1. SUV39H1 methylates histone 3 on lysine 9, creating binding sites for HP1, which further recruits SUV39H1. In the presence of RNA, DNA-PKcs is also recruited by Ku heterodimer, which can phosphorylate HP1α and other proteins. (B) Overexpressed vigilin KH13–14 interacts with SUV39H1 and tritrates it away from heterochromatic regions, resulting in the disruption of the normal function of vigilin in heterochromatin formation.
