Somatic Mutations During an Immune Response inXenopusTadpoles

摘要

The tadpole B-cell repertoire is less diverse than that of the adult frog; their antibodies areof lower affinity and are less heterogenous. In order to determine whether this differenceis due to a lack of or a reduced rate of somatic hypermutation, we analyzed and comparedcDNA sequences utilizing VH1 elements with germline counterparts in isogenic LG7tadpoles during an immune response. Indeed, tadpole VH1 sequences contained somaticmutations. There were zeo to 5 mutations per sequence, all single base-point mutations,with the high ratio of GC to AT base-pair alterations similar to that observed in adult frogs.