Increases DNTT terminal deoxynucleotidyltransferase activity (in vitro). Also acts as a transcriptional regulator, binding to the consensus sequence 5'-GNTGCATG-3' following an AT-tract. Associates with RAB20 promoter and positively regulates its transcription. Binds DNA and nucleosomes; may recruit HDAC1 complexes to nucleosomes or naked DNA. Monomer and homodimer (By similarity). A minor proportion may form homotrimers (By similarity). Interacts with ZNF541 (PubMed:18849567). Interacts with the terminal deoxynucleotidyltransferase DNTT (By similarity). Interacts with TRERF1 (By similarity). Identified in a histone deacetylase complex that contains DNTTIP1, HDAC1 and MIDEAS; this complex assembles into a tetramer that contains four copies of each protein chain (By similarity). Component of a histone deacetylase complex containing DNTTIP1, ZNF541, HDAC1 and HDAC2 (By similarity). The N-terminal domain mediates dimerization. The C-terminal domain mediates interaction with DNA and nucleosomes. It contains a HTH motif that mediates recognition of the consensus sequence.