DNTTIP1 binds DNA and enhances the activity of terminal deoxynucleotidyltransferase (TDT, or DNTT; MIM 187410), a DNA polymerase that catalyzes the polymerization of DNA in the absence of a DNA template (Yamashita et al., 2001 [PubMed 11473582]).[supplied by OMIM, Mar 2008].