BEND3 is a transcriptional repressor that associates with the nucleolar-remodeling complex (NoRC) and is involved in ribosomal DNA (rDNA) silencing []. SUMOylated BEND3 stabilizes the NoRC component Tip5 via USP21 deubiquitinase []. NorC serves as a molecular platform that recruits chromatin modifiers, such as histone deacetylases and histone methyltransferases, leading to deacetylation of histone H4 and trimethylation of H3K9 and H4K20 []. NoRC also targets histone deacetylases and histone methyltransferases to rDNA to establish a heterochromatic state that inhibits transcription activation. Hence, BEND3 and NoRC seem to play a concerted role in the maintenance of heterochromatin architecture [, ].BEND3 has also been shown to mediate Polycomb recruitment in the absence of H3K9Me3 or DNA methylation at the pericentromeric regions []. BEND3 interacts with PICH (ERCC6L), a DNA translocase required for the maintenance of chromosome stability, and stimulates its translocase and ATPase activities. This interaction occurs via an interface between a TPR domain in PICH and a BEN domain in BEND3 [].
