Weber J S, Berry J, Manser T, Claflin J L
Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor 48109-0620.
J Immunol. 1991 May 15;146(10):3652-5.
Somatic hypermutation is known to occur in the VJ kappa exon and its flanking sequences, yet little is known about the hypermutation mechanism or its exact target within the rearranged locus. Mutations may occur at the same frequency, spanning a region from the leader intron to 3' of J kappa 5, regardless of which J is chosen for VJ rearrangement. Another possibility is that mutations may be limited to the rearranged VJ kappa and its immediate flanking sequences. To distinguish between these possibilities, the JC introns of 21 alleles with V kappa rearranged to J kappa 1 were sequenced, and mutations were located. The frequency of mutations was determined for different sections of the intron and compared with the frequencies of mutations found in the JC intron of a set of VJ kappa 5 alleles. The results showed that mutations were concentrated in and around the rearranged VJ, regardless of whether J kappa 1 or J kappa 5 was used. These data imply that the hypermutational mechanism focuses on rearranged V genes.
已知体细胞超突变发生在VJ κ外显子及其侧翼序列中，但对于超突变机制或其在重排基因座内的确切靶点知之甚少。无论选择哪个J进行VJ重排，突变可能以相同频率发生，跨越从前导内含子到J κ 5下游3'的区域。另一种可能性是，突变可能仅限于重排的VJ κ及其紧邻的侧翼序列。为了区分这些可能性，对21个V κ重排至J κ 1的等位基因的JC内含子进行了测序，并确定了突变位置。测定了内含子不同区域的突变频率，并与一组VJ κ 5等位基因的JC内含子中发现的突变频率进行了比较。结果表明，无论使用J κ 1还是J κ 5，突变都集中在重排的VJ及其周围。这些数据表明，超突变机制集中在重排的V基因上。
