Terminal deoxynucleotidyltransferase directly interacts with a novel nuclear protein that is homologous to p65

Citation
N. Yamashita et al., Terminal deoxynucleotidyltransferase directly interacts with a novel nuclear protein that is homologous to p65, GENES CELLS, 6(7), 2001, pp. 641-652
Citations number
31
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Molecular Biology & Genetics
Journal title
GENES TO CELLS
ISSN journal
1356-9597 → ACNP
Volume
6
Issue
7
Year of publication
2001
Pages
641 - 652
Database
ISI
SICI code
1356-9597(200107)6:7<641:TDDIWA>2.0.ZU;2-2
Abstract
Background: Terminal deoxynucleotidyltransferase (TdT) is a DNA polymerase that enhances Ig and TcR gene diversity in the N region in B- and T-cells. TdT is found as a member of a large protein complex in the lysate of the th ymocytes. To elucidate the molecular mechanism of the synthesis of the N re gion, we first attempted to isolate the genes with products that are intera cting directly with TdT. Results: Using a yeast two-hybrid system, we isolated a cDNA clone encoding a novel nuclear protein that interacts with TdT. This protein was designat ed as TdT interacting factor 1 (TdIF1). TdIF1 has a high degree of homology to the transcription factor p65, which belongs to the nuclear receptor sup erfamily. TdIF1 contains HMG-1 and HMG-Y DNA binding domains (AT-hooks) and can bind to single- and double-stranded DNA. TdT and TdIF1 were co-eluted at position 232 kDa by gel filtration of MOLT4 lysate. TdIF1 can enhance Td T activity fourfold in vitro assay system using oligo(dT)(16) as primers. Conclusions: TdIF1 binds directly to TdT, both in vitro and in vivo. TdIF1 and TdT exist as the members of a 232 kDa protein complex. TdIF1 can enhanc e TdT activity maximum fourfold in vitro assay system, suggesting that it p ositively regulates the synthesis of the N region during V(D)J recombinatio n in the Ig and TcR genes.