Terminal deoxynucleotidyltransferase is negatively regulated by direct interaction with proliferating cell nuclear antigen

Citation
S. Ibe et al., Terminal deoxynucleotidyltransferase is negatively regulated by direct interaction with proliferating cell nuclear antigen, GENES CELLS, 6(9), 2001, pp. 815-824
Citations number
49
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Molecular Biology & Genetics
Journal title
GENES TO CELLS
ISSN journal
1356-9597 → ACNP
Volume
6
Issue
9
Year of publication
2001
Pages
815 - 824
Database
ISI
SICI code
1356-9597(200109)6:9<815:TDINRB>2.0.ZU;2-K
Abstract
Background: The repertoires of Ig and TcR are generated by a combinatorial rearrangement of variable (V), diversity (D), and joining (J) segments (V(D )J recombination) in B- and T-cells. Terminal deoxynucleotidyltransferase ( TdT) adds extra nucleotides (N nucleotides) at the junctions of the gene se gments to enhance the Ig and TcR genes diversity. Using an anti-TdT antibod y column, TdT has been purified as a member of a megadalton protein complex from rat thymus. The N region would be synthesized with the large protein complex. Results: The cDNAs for proliferating cell nuclear antigen (PCNA) were isola ted by yeast two-hybrid screening as the gene products which directly inter acted with TdT. The interaction between PCNA and TdT was confirmed by co-im munoprecipitation, both in vitro and in vivo. TdT binds directly to a PCNA trimer, as shown by gel filtration. TdT interacts with PCNA in its DNA poly merization domain (DPD), but not in its BRCA-1 C-terminal (BRCT) domain. Td T activity was reduced to 17% of the maximum value by TdT/PCNA complex form ation. Conclusion: TdT interacts directly with PCNA through its DPD. A functional consequence of this interaction is the negative regulation of TdT activity These findings suggest that TdT catalyses the addition of N nucleotides und er the negative control of PCNA during V(D)J recombination.