The Translesion DNA Polymerase Theta Plays a Dominant Role in Immunoglobulin Gene Somatic Hypermutation
Overview
Molecular Biology
Authors
Affiliations
Immunoglobulin (Ig) somatic hypermutation (SHM) critically underlies the generation of high-affinity antibodies. Mutations can be introduced by error-prone polymerases such as polymerase zeta (Rev3), a mispair extender, and polymerase eta, a mispair inserter with a preference for dA/dT, while repairing DNA lesions initiated by AID-mediated deamination of dC to yield dU:dG mismatches. The partial impairment of SHM observed in the absence of these polymerases led us to hypothesize a main role for another translesion DNA polymerase. Here, we show that deletion in C57BL/6J mice of the translesion polymerase theta, which possesses a dual nucleotide mispair inserter-extender function, results in greater than 60% decrease of mutations in antigen-selected V186.2DJ(H) transcripts and greater than 80% decrease in mutations in the Ig H chain intronic J(H)4-iEmu sequence, together with significant alterations in the spectrum of the residual mutations. Thus, polymerase theta plays a dominant role in SHM, possibly by introducing mismatches while bypassing abasic sites generated by UDG-mediated deglycosylation of AID-effected dU, by extending DNA past such abasic sites and by synthesizing DNA during dU:dG mismatch repair.
Molecular mechanisms of DNA lesion and repair during antibody somatic hypermutation.
Hao Q, Li J, Yeap L Sci China Life Sci. 2024; 67(11):2344-2353.
PMID: 39048716 DOI: 10.1007/s11427-024-2615-1.
Implications of Translesion DNA Synthesis Polymerases on Genomic Stability and Human Health.
Venkadakrishnan J, Lahane G, Dhar A, Xiao W, Bhat K, Pandita T Mol Cell Biol. 2023; 43(8):401-425.
PMID: 37439479 PMC: 10448981. DOI: 10.1080/10985549.2023.2224199.
B cell class switch recombination is regulated by DYRK1A through MSH6 phosphorylation.
Stoler-Barak L, Harris E, Peres A, Hezroni H, Kuka M, Di Lucia P Nat Commun. 2023; 14(1):1462.
PMID: 36927854 PMC: 10020581. DOI: 10.1038/s41467-023-37205-5.
Resistance to DNA repair inhibitors in cancer.
Baxter J, Zatreanu D, Pettitt S, Lord C Mol Oncol. 2022; 16(21):3811-3827.
PMID: 35567571 PMC: 9627783. DOI: 10.1002/1878-0261.13224.
Unravelling roles of error-prone DNA polymerases in shaping cancer genomes.
Vaziri C, Rogozin I, Gu Q, Wu D, Day T Oncogene. 2021; 40(48):6549-6565.
PMID: 34663880 PMC: 8639439. DOI: 10.1038/s41388-021-02032-9.