Deoxyuridine triphosphate incorporation during somatic hypermutation of mouse VkOx genes after immunization with phenyloxazolone.
Somatic hypermutation (SHM) of Ig genes is the result of a two-phase process initiated by activation-induced cytidine deaminase, relying on two different strategies for the introduction of mutations at CG pairs (phase I) and at AT pairs (phase II). To explain the selectivity of phase II, two mechanisms were proposed: AT-selective error-prone DNA-polymerases, deoxyuridine triphosphate (dUTP) incorporation, or both. However, there has been no experimental evidence so far of the possible involvement of the latter. We have developed a ligation-anchored PCR method based on the formation of single-strand breaks at uracils. In this study, we show the presence of uracil in hypermutating VkOx genes in wild type (AID(+/+)) mice, demonstrating that dUTP incorporation via DNA polymerases could be a major mechanism in SHM. Thus, error-prone DNA polymerases would participate in SHM via low-fidelity replication and incorporation of dUTP.
Roche
Benjamin
B
Unité de Génétique et Biochimie du Développement and Unité de Recherche Associée, Centre National de la Recherche Scientifique 2581, Institut Pasteur, Paris, France.
Claës
Aurélie
A
Rougeon
François
F
D000818:Animals; D003856:Deoxyuracil Nucleotides / Q000235:genetics*; D005803:Genes, Immunoglobulin; D007145:Immunoglobulin kappa-Chains / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D010081:Oxazolone / Q000031:analogs & derivatives* / Q000276:immunology; D016133:Polymerase Chain Reaction; D027041:Somatic Hypermutation, Immunoglobulin / Q000235:genetics*
D003856:Deoxyuracil Nucleotides; D007145:Immunoglobulin kappa-Chains; C027078:deoxyuridine triphosphate; C018361:2-phenyloxazolone; D010081:Oxazolone