TY - JOUR
T1 - DNA-PKcs and Artemis function in the end-joining phase of immunoglobulin heavy chain class switch recombination
AU - Franco, Sonia
AU - Murphy, Michael M.
AU - Li, Gang
AU - Borjeson, Tiffany
AU - Boboila, Cristian
AU - Alt, Frederick W.
PY - 2008/3/17
Y1 - 2008/3/17
N2 - The DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and Artemis are classical nonhomologous DNA end-joining (C-NHEJ) factors required for joining a subset of DNA double-strand breaks (DSB), particularly those requiring end processing. In mature B cells, activation-induced cytidine deaminase (AID) initiates class switch recombination (CSR) by introducing lesions into S regions upstream of two recombining CH exons, which are processed into DSBs and rejoined by C-NHEJ to complete CSR. The function of DNA-PKcs in CSR has been controversial with some reports but not others showing that DNA-PKcs-deficient mice are significantly impaired for CSR. Artemis-deficient B cells reportedly undergo CSR at normal levels. Overall, it is still not known whether there are any CSR-associated DSBs that require DNA-PKcs and/or Artemis to be joined. Here, we have used an immunoglobulin (Ig)H locus-specific fluorescent in situ hybridization assay to unequivocally demonstrate that both DNA-PKcs and, unexpectedly, Artemis are necessary for joining a subset of AID-dependent DSBs. In the absence of either factor, B cells activated for CSR frequently generate AID-dependent IgH locus chromosomal breaks and translocations. We also find that under specific activation conditions, DNA-PKcs-/- B cells with chromosomal breaks are eliminated or at least prevented from progressing to metaphase via a p53-dependent response. JEM
AB - The DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and Artemis are classical nonhomologous DNA end-joining (C-NHEJ) factors required for joining a subset of DNA double-strand breaks (DSB), particularly those requiring end processing. In mature B cells, activation-induced cytidine deaminase (AID) initiates class switch recombination (CSR) by introducing lesions into S regions upstream of two recombining CH exons, which are processed into DSBs and rejoined by C-NHEJ to complete CSR. The function of DNA-PKcs in CSR has been controversial with some reports but not others showing that DNA-PKcs-deficient mice are significantly impaired for CSR. Artemis-deficient B cells reportedly undergo CSR at normal levels. Overall, it is still not known whether there are any CSR-associated DSBs that require DNA-PKcs and/or Artemis to be joined. Here, we have used an immunoglobulin (Ig)H locus-specific fluorescent in situ hybridization assay to unequivocally demonstrate that both DNA-PKcs and, unexpectedly, Artemis are necessary for joining a subset of AID-dependent DSBs. In the absence of either factor, B cells activated for CSR frequently generate AID-dependent IgH locus chromosomal breaks and translocations. We also find that under specific activation conditions, DNA-PKcs-/- B cells with chromosomal breaks are eliminated or at least prevented from progressing to metaphase via a p53-dependent response. JEM
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U2 - 10.1084/jem.20080044
DO - 10.1084/jem.20080044
M3 - Article
C2 - 18316419
AN - SCOPUS:41149099048
VL - 205
SP - 557
EP - 564
JO - Journal of Experimental Medicine
JF - Journal of Experimental Medicine
SN - 0022-1007
IS - 3
ER -