Association of nuclear matrix antigens with exon-containing splicing complexes.
Association of nuclear matrix antigens with exon-containing splicing complexes.
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DOI：
10.1083/jcb.127.3.593
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发表时间：
1994-11
期刊：
影响因子：
--
通讯作者：
Sharp PA
中科院分区：
文献类型：
--
作者：
Blencowe BJ;Nickerson JA;Issner R;Penman S;Sharp PA
针对人核基质（抗NM）1 mAb产生的mAb已用于研究核基质抗原在前mRNA加工中的作用。本研究中使用的三种抗NM mAb识别高度定位于核基质斑点的抗原。令人惊讶的是，所有这三种mAb优先免疫沉淀含有外显子序列的剪接复合物。抗NM mAb有效地免疫沉淀外显子产物复合物，但在剪接的第二步后不免疫沉淀含有lactinase产物的复合物。两种抗NM mAb在体外完全抑制前mRNA剪接。然而，没有一种抗NM mAb似乎识别与剪接snRNP稳定相关的因子。三种抗NM mAb主要与不同的高分子量抗原反应，这些抗原属于一类在高Mg 2+浓度存在下选择性地与Ser-Arg蛋白剪接因子沉淀的核蛋白。免疫学、生物化学和细胞生物学数据表明，两种NM抗原与所定义的Ser-Arg蛋白质组相关。结果表明，存在一个扩展的Ser-Arg家族作为一个组成部分的核基质。
mAbs raised against the human nuclear matrix (anti-NM)1 mAbs have been used to investigate the role of nuclear matrix antigens in pre-mRNA processing. The three anti-NM mAbs used in this study recognize antigens that are highly localized to nuclear matrix speckles. Surprisingly, all three of these mAbs preferentially immunoprecipitate splicing complexes containing exon sequences. The anti-NM mAbs efficiently immunoprecipitate the exon product complex but not complexes containing the lariat product after the second step of splicing. Two of the anti-NM mAbs completely inhibit pre-mRNA splicing in vitro. However, none of the anti-NM mAbs appear to recognize factors stably associated with splicing snRNPs. The three anti-NM mAbs predominantly react with distinct high molecular weight antigens, which belong to a class of nuclear proteins that selectively precipitate with Ser-Arg protein-splicing factors in the presence of high Mg2+ concentrations. Immunological, biochemical, and cell biological data indicate that two of the NM antigens are related to the defined set of Ser-Arg proteins. The results suggest the existence of an extended Ser- Arg family as a component of the nuclear matrix.