A shuttle vector system for the investigation of immunoglobulin gene hypermutation: absence of enhanced mutability in intermediate B cell lines.
A shuttle vector system for the investigation of immunoglobulin gene hypermutation: absence of enhanced mutability in intermediate B cell lines.
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DOI：
10.1016/0161-5890(92)90140-s
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发表时间：
1992-07
影响因子：
3.6
通讯作者：
J. Johnston;M. Yu;W. Carroll
中科院分区：
文献类型：
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作者：
J. Johnston;M. Yu;W. Carroll
针对免疫球蛋白（IG）基因座重排的V（D）J区段的体细胞超突变实质上有助于抗体基因多样化。然而，无论是精确的B细胞亚群的超突变，也不知道的分子机制。一个模型提出，IG片段可能是唯一易受DNA切口和随后的易错修复在特定的B细胞发育阶段。我们描述了一个基于SV 40的穿梭载体系统来测试这样的模型。含有两个不同的IG片段并置到thesupF标记基因的质粒已经通过代表B细胞发育中间阶段的细胞系传代，拯救并筛选标记基因突变。到目前为止，我们还没有在任何检测的细胞系中证实增强的supF突变，无论相邻的IG片段如何。因此，这些细胞系表现出正常的DNA修复机制，并且没有证据表明在测试的IG区段上核酸内切酶活性增加。该系统的可行性将允许使用暴露于更宽范围的B细胞的其他IG靶序列进行类似的实验。
Somatic hypermutation focused to the rearranged V(D)J segment of the immunoglobulin (Ig) loci contributes substantially to antibody gene diversification. However, neither the precise B cell subset subject to hypermutation nor the molecular mechanism(s) involved is known. One model proposes that Ig segments may be uniquely susceptible to DNA nicking and subsequent error-prone repair during a specific B cell developmental stage. We describe an SV40-based shuttle vector system for testing such a model. Plasmids containing two distinct Ig segments juxtaposed to thesupFmarker gene have been passaged through cell lines representing intermediate stages of B cell development, rescued and screened for marker gene mutations. To date we have not demonstrated enhancedsupFmutation in any cell line examined, irrespective of the adjacent Ig segment. Thus, these cell lines exhibit normal DNA repair mechanisms and no evidence of increased endonuclease activity on the Ig segments tested. The feasibility of this system will allow similar experiments using other Ig target sequences exposed to a broader range of B cells.