Alternative titles; symbols
HGNC Approved Gene Symbol: DNTTIP1
Cytogenetic location: 20q13.12 Genomic coordinates (GRCh38) : 20:45,791,954-45,811,418 (from NCBI)
DNTTIP1 binds DNA and enhances the activity of terminal deoxynucleotidyltransferase (TDT, or DNTT; 187410), a DNA polymerase that catalyzes the polymerization of DNA in the absence of a DNA template (Yamashita et al., 2001).
Using yeast 2-hybrid analysis to screen a human thymus cDNA library with full-length TDT as bait, Yamashita et al. (2001) cloned DNTTIP1, which they called TDIF1. The deduced 329-amino acid protein has a calculated molecular mass of 37 kD and shares 96.4% homology with the mouse homolog. DNTTIP1 shares homology with p65 (RELA; 164014) over the C-terminal region and with HMGI-C (HMGA2; 600698) over the HMG-I and HMG-Y DNA-binding domains (AT hooks). Immunofluorescence studies localized DNTTIP1 to the nucleus, consistent with the presence of an N-terminal nuclear localization signal.
Using GST pull-down, immunoprecipitation, and deletion mutant experiments, Yamashita et al. (2001) showed that DNTTIP1 binds to the C-terminal region of TDT. Yeast 2-hybrid analysis and gel filtration studies showed that DNTTIP1 also binds to itself to form dimers. Gel filtration experiments suggested that DNTTIP1 and TDT form a 232-kD protein complex. An in vitro activity assay showed that DNTTIP1 enhanced TDT activity in the presence of activated DNA oligo(dT)16 or oligo(dA)12-18 primers, but had no effect with oligo(dC)10 or oligo(dG)12-18 primers. Using a DNA cellulose column, Yamashita et al. (2001) showed that the N-terminal AT hook-containing region of DNTTIP1 mediates DNTTIP1-DNA binding.
Yamashita et al. (2001) determined that the DNTTIP1 gene contains 13 exons.
By genomic sequence analysis, Yamashita et al. (2001) mapped the DNTTIP1 gene to chromosome 20q12-q13.
Yamashita, N., Shimazaki, N., Ibe, S., Kaneko, R., Tanabe, A., Toyomoto, T., Fujita, K., Hasegawa, T., Toji, S., Tamai, K., Yamamoto, H., Koiwai, O. Terminal deoxynucleotidyltransferase directly interacts with a novel nuclear protein that is homologous to p65. Genes Cells 6: 641-652, 2001. [PubMed: 11473582] [Full Text: https://doi.org/10.1046/j.1365-2443.2001.00449.x]