A cis-acting diversification activator both necessary and sufficient for AID-mediated hypermutation.
A cis-acting diversification activator both necessary and sufficient for AID-mediated hypermutation.
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顺式作用多样化激活剂对于 AID 介导的超突变来说是必要且充分的。
DOI：
10.1371/journal.pgen.1000332
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发表时间：
2009-01
期刊：
影响因子：
4.5
通讯作者：
Buerstedde, Jean-Marie
中科院分区：
文献类型：
--
作者：
Blagodatski, Artem;Batrak, Vera;Schmidl, Sabine;Schoetz, Ulrike;Caldwell, Randolph B.;Arakawa, Hiroshi;Buerstedde, Jean-Marie
免疫球蛋白 (Ig) 基因的超突变需要激活诱导胞苷脱氨酶 (AID) 和转录，但目前尚不清楚为什么 B 细胞的其他转录基因不会发生突变。我们描述了一种报告基因转基因，当插入 DT40 B 细胞系的 Ig 轻链 (IgL) 基因座或附近时，会因超突变而受损，但当插入其他染色体位置时，该基因仍能稳定表达。 IgL 基因座的逐步删除揭示了 IgL 转录起始位点下游延伸 9.8 kb 的序列赋予了超突变活性。该序列被命名为 DIVAC（多样化激活剂），当插入非 Ig 位点时，可有效激活超突变。这些结果显着扩展了之前报道的 AID 介导的基因多样化的发现。他们通过删除和插入分析表明，顺式作用序列使邻近的转录单位易于发生超突变。 AID 介导的基因多样化如何靶向免疫球蛋白位点仍然是一个悬而未决的问题。在这里，我们定义了一个顺式作用序列，命名为 DIVAC（多样化激活剂），它是 Ig 轻链基因超突变所必需的，并且足以激活 DT40 B 细胞系中各个非 Ig 位点的超突变。 DIVAC 由多个相互作用的序列组成，能够在其靶基因的上游和下游相当长的距离内发挥作用。这项工作提供了第一个确凿的证据，证明 AID 介导的基因多样化是通过顺式作用序列靶向 Ig 位点的。脊椎动物进化过程中 AID 介导的 Ig 基因多样化的保守性表明 DIVAC 在哺乳动物 B 细胞的基因转换、超突变和转换重组中也发挥着作用。这些发现不仅应该引起分子免疫学和 B 细胞淋巴瘤发病机制的普遍兴趣，而且应该引起整个生物学领域的普遍兴趣，作为如何控制位点特异性基因多样化的独特例子。所描述的实验系统为进一步阐明 DIVAC 的分子机制提供了独特的优势。
Hypermutation of the immunoglobulin (Ig) genes requires Activation Induced cytidine Deaminase (AID) and transcription, but it remains unclear why other transcribed genes of B cells do not mutate. We describe a reporter transgene crippled by hypermutation when inserted into or near the Ig light chain (IgL) locus of the DT40 B cell line yet stably expressed when inserted into other chromosomal positions. Step-wise deletions of the IgL locus revealed that a sequence extending for 9.8 kilobases downstream of the IgL transcription start site confers the hypermutation activity. This sequence, named DIVAC for diversification activator, efficiently activates hypermutation when inserted at non-Ig loci. The results significantly extend previously reported findings on AID-mediated gene diversification. They show by both deletion and insertion analyses that cis-acting sequences predispose neighboring transcription units to hypermutation. It remains an open question how AID-mediated gene diversification is targeted to the immunoglobulin loci. Here we define a cis-acting sequence, named DIVAC for diversification activator, which is required for hypermutation of the Ig light chain gene and sufficient to activate hypermutation at various non-Ig loci in the DT40 B cell line. DIVAC is composed of multiple interacting sequences and able to work over considerable distances both upstream and downstream of its target gene. This work provides the first conclusive evidence that AID-mediated gene diversification is targeted to the Ig loci by cis-acting sequences. The conservation of AID-mediated Ig gene diversification during vertebrate evolution suggests that DIVACs also play a role in gene conversion, hypermutation, and switch recombination in mammalian B cells. The findings should be of general interest not only for molecular immunology and the pathogenesis of B cell lymphomas but also the whole field of biology as a unique example of how locus-specific gene diversification is controlled. The described experimental system offers unique advantages to further clarify the molecular mechanism of DIVAC.
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影响因子：
64.5
作者：
BETZ, AG;MILSTEIN, C;NEUBERGER, MS
通讯作者：
NEUBERGER, MS
影响因子：
3.6
作者：
Gopal, Anjali R.;Fugmann, Sebastian D.
通讯作者：
Fugmann, Sebastian D.
影响因子：
64.8
作者：
Liu, Man;Duke, Jamie L.;Schatz, David G.
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Schatz, David G.
激活诱导的脱氨酶（AID）在免疫球蛋白SMU区域中指导的超名：在类开关重组和体细胞超伪装的共同步骤中，援助参与的意义。
影响因子：
15.3
作者：
Nagaoka, Hitoshi;Muramatsu, Masamichi;Yamamura, Namiko;Kinoshita, Kazuo;Honjo, Tasuku
通讯作者：
Honjo, Tasuku
影响因子：
14.9
作者：
Arakawa H;Kudo H;Batrak V;Caldwell RB;Rieger MA;Ellwart JW;Buerstedde JM
通讯作者：
Buerstedde JM