Switch recombination breakpoints are strictly correlated with DNA recognition motifs for immunoglobulin S gamma 3 DNA-binding proteins.
Switch recombination breakpoints are strictly correlated with DNA recognition motifs for immunoglobulin S gamma 3 DNA-binding proteins.
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DOI：
10.1084/jem.176.2.339
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发表时间：
1992-08-01
期刊：
影响因子：
--
通讯作者：
Kenter AL
中科院分区：
文献类型：
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作者：
Wuerffel R;Jamieson CE;Morgan L;Merkulov GV;Sen R;Kenter AL
开关(S)重组的缺失环出模型预测开关区域之间的中间DNA将作为一个圆被切除。免疫球蛋白开关重组的环状切除产物最近从脂多糖（LPS）刺激的脾细胞中分离出来。这些大圆圈中的重组断点被发现落在开关区域内。由于开关重组明显集中在开关区域，我们假设一些dna结合蛋白因子可能在重组前特异性地识别和促进开关区域的对齐。两种dna结合蛋白与S γ 3串联重复序列的两个离散区域特异性相互作用，已在LPS和葡聚糖硫酸盐（DxS）激活的脾B细胞的粗提物和部分纯化核提取物中被鉴定出来。通过迁移迁移试验、甲基化干扰、竞争结合研究和使用p50成分特异性抗血清的超迁移分析，发现第一个因子与NF-kappa B没有区别。第二种似乎是由两种紧密移动的流动性组成，它们在部分净化后不会分离。通过甲基化干扰分析和竞争结合分析，第二种复合物对S γ 3是独特的和特异性的。对S γ 3开关区发生重组的位点进行了分析，发现它们与S γ 3开关结合蛋白的结合位点严格相关。
The deletion looping out model of switch (S) recombination predicts that the intervening DNA between switch regions will be excised as a circle. Circular excision products of immunoglobulin switch recombination have been recently isolated from lipopolysaccharide (LPS)- stimulated spleen cells. The recombination breakpoints in these large circles were found to fall within switch regions. Since switch recombination is clearly focused on switch regions, we hypothesized that some DNA-binding protein factor might be involved in specifically recognizing and facilitating the alignment of switch regions before recombination. Two DNA-binding proteins that specifically interact with two discrete regions of the S gamma 3 tandem repeat have been identified in crude and partially purified nuclear extracts derived from LPS- and dextran sulfate (DxS)-activated splenic B cells. The first factor has been found indistinguishable from NF-kappa B by mobility shift assays, methylation interference, competition binding studies, and supershift analysis using an antiserum specific for the p50 component. The second appears to be composed of two closely traveling mobilities that do not separate upon partial purification. This second complex is unique and specific for S gamma 3 by methylation interference assays and competition-binding analysis. The sites at which recombination occurs in the S gamma 3 switch region have been analyzed and found to strictly correlate with the binding sites of the S gamma 3 switch binding proteins.