Increases DNTT terminal deoxynucleotidyltransferase activity (in vitro) (PubMed:11473582). 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 (PubMed:11473582, PubMed:25653165). A minor proportion may form homotrimers (PubMed:11473582). Interacts with ZNF541 (PubMed:21573134). Interacts with the terminal deoxynucleotidyltransferase DNTT (PubMed:11473582, PubMed:16371131). Interacts with TRERF1 (PubMed:16371131, PubMed:21573134). 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 (PubMed:25653165). Component of a histone deacetylase complex containing DNTTIP1, ZNF541, HDAC1 and HDAC2 (PubMed:21573134). The N-terminal domain mediates dimerization. The C-terminal domain mediates interaction with DNA and nucleosomes (PubMed:11473582, PubMed:25653165). It contains a HTH motif that mediates recognition of the consensus sequence (PubMed:23874396).