免疫球蛋白单个转换区在类别转换时基因突变的研究

Study on gene mutations of single S region in immunoglobulin class switch recombination

目的:观察在免疫球蛋白的类别转换(CSR)过程中单个转换区(S区)的基因重组情况。方法:通过构建包含单个S区(FS-α2)基因序列的人工载体,使目的基因位于四环素敏感的启动子下游,并转染到一株能够在体外诱导CSR反应的B淋巴细胞系,经细胞因子诱导CSR后,用PCR扩增目的基因,再进行序列分析以观察此S区基因的变异及其依赖的因素。结果:在细胞因子的诱导下,单个S区基因在CSR时可以出现基因变异包括点突变、序列缺失及序列插入等变化,并且当抑制上游启动子时,S区基因变异显著下降,表明S区基因重组受控于基因转录。结论:CSR重组机制在单个S区中同样发挥作用。

Objective：To investigate the gene rearrangements in immunoglobulin single switch （S） region during class switch recombination. Methods：An artificial substrate containing single S region （FSα-2） driven by tetracycllne-responsive promoter was comtmcted and underwent CSR in a switch-inducible B lymphoma line was stimulated by cytokines,then the S region mutations and its dependent factors were detected by detected PCR and sequencing. Results： C, ene rearrangements including deletions, insertions as well as point mutations could occur even in this single S region after cytokines stimulation;Furthermore, when the upstream promoter, was suppressed by its inhibitor, CSR frequency was significantly decreased, indicating a transcription dependent S region recombination. Conclusion： Class switch recombination mechanism can exert a similar effect on single S region.