Identification of murine B cell lines that undergo somatic hypermutation focused to A:T and G:C residues
Identification of murine B cell lines that undergo somatic hypermutation focused to A:T and G:C residues
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DOI：
10.1002/eji.200737664
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发表时间：
2008-01-01
影响因子：
5.4
通讯作者：
Kenter, Amy L.
中科院分区：
文献类型：
--
作者：
Bhattacharya, Palash;Grigera, Fernando;Kenter, Amy L.
激活诱导脱氨酶(AID)是类开关重组(CSR)和体细胞高突变(SHM)的主要调节因子，但其调控机制尚不清楚。三个IgM(+)/AID(+)和两个Ig G(+)/AID(+)B细胞株中转换质粒活性的不同模式促使对全球基因表达的分析，以发现这些细胞的起源。基因图谱显示，免疫球蛋白G(+)/艾滋病(+)B细胞系来源于生发中心B细胞。SHM电势分析表明，在体外培养过程中，IgV kappa结构域以较高的速度诱导多样化。突变谱聚焦于A：T碱基对，揭示了在SHM的第二阶段优先发生的超突变程序的一个组成部分。分析了A：T误差谱，不是聚合酶ETA活性的特征。在WT型和POL型ETA-、Msh2-和MSH6缺失的B细胞中，观察到三种用于A：T碱基替换的共有基序的差异模式。值得注意的是，我们B细胞系中的突变分别概括了Pol ETA和Msh2缺乏症的可变基序图谱，并表明SHM中A：T突变的另一条产生途径在小鼠和人类中是保守的。
Activation-induced deaminase (AID) is the master regulator of class switch recombination (CSR) and somatic hypermutation (SHM), but the mechanisms regulating AID function are obscure. The differential pattern of switch plasmid activity in three IgM(+)/AID(+) and two IgG(+)/AID(+) B cell lines prompted an analysis of global gene expression to discover the origin of these cells. Gene profiling suggested that the IgG(+)/AID(+) B cell lines derived from germinal center B cells. Analysis of SHM potential demonstrates that the IgV kappa domains are inducibly diversified at high rate during in vitro culture. The mutation spectra focused to A:T base pairs, revealing a component of the hypermutation program that occurs preferentially during phase 2 of SHM. The A:T error spectra were analyzed and were not characteristic of polymerase eta activity. A differential pattern of three consensus motifs used for A:T base substitutions was observed in WTand Pol eta-, Msh2- and Msh6 -deficient B cells. Strikingly, mutations in our B cell lines recapitulated the mutable motif profile for Pol eta and Msh2 deficiency, respectively, and suggest that an additional pathway for the generation of A:T mutations in SHM is conserved in mouse and human.