Pol zeta ablation in B cells impairs the germinal center reaction, class switch recombination, DNA break repair, and genome stability.
Pol zeta is an error-prone DNA polymerase that is critical for embryonic development and maintenance of genome stability. To analyze its suggested role in somatic hypermutation (SHM) and possible contribution to DNA double-strand break (DSB) repair in class switch recombination (CSR), we ablated Rev3, the catalytic subunit of Pol zeta, selectively in mature B cells in vivo. The frequency of somatic mutation was reduced in the mutant cells but the pattern of SHM was unaffected. Rev3-deficient B cells also exhibited pronounced chromosomal instability and impaired proliferation capacity. Although the data thus argue against a direct role of Pol zeta in SHM, Pol zeta deficiency directly interfered with CSR in that activated Rev3-deficient B cells exhibited a reduced efficiency of CSR and an increased frequency of DNA breaks in the immunoglobulin H locus. Based on our results, we suggest a nonredundant role of Pol zeta in DNA DSB repair through nonhomologous end joining.
Schenten
Dominik
D
Immune Disease Institute, Boston, MA 02115, USA.
Kracker
Sven
S
Esposito
Gloria
G
Franco
Sonia
S
Klein
Ulf
U
Murphy
Michael
M
Alt
Frederick W
FW
Rajewsky
Klaus
K
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D043171:Chromosomal Instability / Q000276:immunology*; D020732:Cytogenetic Analysis; D017931:DNA Primers / Q000235:genetics; D004260:DNA Repair; D004259:DNA-Directed DNA Polymerase / Q000172:deficiency / Q000235:genetics / Q000276:immunology; D005434:Flow Cytometry; D018858:Germinal Center / Q000276:immunology*; D017578:Immunoglobulin Class Switching / Q000276:immunology*; D051379:Mice; D008856:Microscopy, Fluorescence; D027041:Somatic Hypermutation, Immunoglobulin / Q000276:immunology*
D017931:DNA Primers; D004259:DNA-Directed DNA Polymerase; C425929:DNA polymerase zeta; C486862:REV3L protein, mouse