Elsevier, Immunology Letters, 1(125), p. 22-30, 2009
DOI: 10.1016/j.imlet.2009.05.005
Full text: Unavailable
Somatic hypermutation (SHM) diversifies the rearranged immunoglobulin variable (V) region gene in B cells, contributing to affinity maturation of antibodies. It is believed that SHM is generated either by direct replication or by error-prone repair systems resolving V region DNA lesions caused directly or indirectly by cytidine deaminase AID. In accord with a part of these mechanisms, it was reported that SHM is associated with staggered double-strand DNA breaks (DSBs) occurring in the rearranged V regions. However, endonucleases responsible for the DSBs remain elusive. Here we show that DNase gamma, a member of DNase I family endonucleases, contributes to the generation of SHM including point mutation, and nucleotide insertion and deletion in chicken DT40 B cell line. DNase gamma also contributes to the generation of staggered DSBs in the rearranged V region. These results raise a possibility that DNase gamma is involved in the V gene mutation machinery.