The function of DNTTIP1 (deoxynucleotidyltransferase terminal interacting protein 1, ENSG00000101457) is as follows. 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. {ECO:0000269|PubMed:11473582, ECO:0000269|PubMed:23874396, ECO:0000305|PubMed:25653165}.