| First Author | Roa S | Year | 2008 |
| Journal | Proc Natl Acad Sci U S A | Volume | 105 |
| Issue | 42 | Pages | 16248-53 |
| PubMed ID | 18854411 | Mgi Jnum | J:141098 |
| Mgi Id | MGI:3815369 | Doi | 10.1073/pnas.0808182105 |
| Citation | Roa S, et al. (2008) Ubiquitylated PCNA plays a role in somatic hypermutation and class-switch recombination and is required for meiotic progression. Proc Natl Acad Sci U S A 105(42):16248-53 |
| abstractText | Somatic hypermutation (SHM) and class-switch recombination (CSR) of Ig genes are dependent upon activation-induced cytidine deaminase (AID)-induced mutations. The scaffolding properties of proliferating cell nuclear antigen (PCNA) and ubiquitylation of its residue K164 have been suggested to play an important role organizing the error-prone repair events that contribute to the AID-induced diversification of the Ig locus. We generated knockout mice for PCNA (Pcna(-/-)), which were embryonic lethal. Expression of PCNA with the K164R mutation rescued the lethal phenotype, but the mice (Pcna(-/-)tg(K164R)) displayed a meiotic defect in early pachynema and were sterile. B cells proliferated normally in Pcna(-/-)tg(K164R) mice, but a PCNA-K164R mutation resulted in impaired ex vivo CSR to IgG1 and IgG3, which was associated with reduced mutation frequency at the switch regions and a bias toward blunt junctions. Analysis of the heavy chain V186.2 region after NP-immunization showed in Pcna(-/-)tg(K164R) mice a significant reduction in the mutation frequency of A:T residues in WA motifs preferred by polymerase-eta (Poleta), and a strand-biased increase in the mutation frequency of G residues, preferentially in the context of AID-targeted GYW motifs. The phenotype of Pcna(-/-)tg(K164R) mice supports the idea that ubiquitylation of PCNA participates directly in the meiotic process and the diversification of the Ig locus through class-switch recombination (CSR) and somatic hypermutation (SHM). |
