Signal joint formation is also impaired in DNA-dependent protein kinase catalytic subunit knockout cells

R. Fukumura, R. Araki, A. Fujimori, Y. Tsutsumi, A. Kurimasa, G. C. Li, D. J. Chen, K. Tatsumi, M. Abe

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


The effort to elucidate the mechanism of V(D)J recombination has given rise to a dispute as to whether DNA-dependent protein kinase catalytic subunit (DNA-PKcs) contributes to signal joint formation (sjf). Observations reported to date are confusing. Analyses using DNA-PKcs-deficient cells could not conclude the requirement of DNA-PKcs for sjf, because sjf can be formed by end-joining activities which are diverse among cells other than those participating in V(D)J recombination. Here, we observed V(D)J recombination in DNA-PKcs knockout cells and showed that both signal and coding joint formation were clearly impaired in the cells. Subsequently, to directly demonstrate the requirement of DNA-PKcs for sjf, we introduced full-length cDNA of DNA-PKcs into the knockout cells. Furthermore, several mutant DNA-PKcs cDNA constructs designed from mutant cell lines (irs-20, V3, murine scid, and SX9) were also introduced into the cells to obtain further evidence indicating the involvement of DNA-PKcs in sjf. We found as a result that the full-length cDNA complemented the aberrant sjf and that the mutant cDNAs constructs also partially complemented it. Lastly, we looked at whether the kinase activity of DNA-PKcs is necessary for sjf and, as a result, demonstrated a close relationship between them. Our observations clearly indicate that the DNA-PKcs controls not only coding joint formation but also the sjf in V(D)J recombination through its kinase activity.

Original languageEnglish (US)
Pages (from-to)3883-3889
Number of pages7
JournalJournal of Immunology
Issue number7
StatePublished - Oct 1 2000

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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