Smith H C, Ochs R L, Fernandez E A, Spector D L
Mol Cell Biochem. 1986 May;70(2):151-68. doi: 10.1007/BF00229430.
Polyclonal antibodies have been produced which react with a nuclear protein having a molecular weight of 107kD and a pI of 8.7-8.8 (designated p107). This protein is shown to be a component of the residual ribonucleoprotein (RNP) network of the nuclear matrix. P107 localized exclusively to the nuclear interior but not within nucleolar or chromatin domains. We have taken advantage of this unique probe to examine whether the RNP network of the isolated nuclear matrix has a physical counterpart in situ. We show that RNA, p107, divalent cations and the 28 kD Sm antigen of U-snRNPs are components of in situ macromolecular assemblies. While the morphology and intranuclear distribution of these assemblies are insensitive to the removal of chromatin, they are markedly altered by degradation of RNA. Digestion in situ of RNA in the presence of EDTA followed by extraction with high ionic strength buffers solubilized the components of these assemblies. Electron microscopic and immunobiochemical data are presented which support the concept that the residual RNP network of the nuclear matrix is an isolate of a pre-existing structure, and that perturbations in this internal network can be created by RNA degradation, depletion of essential metal ions and proteolysis.
已产生了与一种分子量为107kD、等电点为8.7 - 8.8的核蛋白（命名为p107）发生反应的多克隆抗体。该蛋白被证明是核基质残余核糖核蛋白（RNP）网络的一个组成部分。P107仅定位于核内部，而不在核仁或染色质区域内。我们利用这种独特的探针来研究分离的核基质的RNP网络在原位是否有对应的物理结构。我们发现RNA、p107、二价阳离子和U - snRNPs的28kD Sm抗原是原位大分子组装体的组成部分。虽然这些组装体的形态和核内分布对染色质的去除不敏感，但RNA的降解会使其发生显著改变。在EDTA存在的情况下对RNA进行原位消化，然后用高离子强度缓冲液提取，可溶解这些组装体的成分。本文提供了电子显微镜和免疫生化数据，支持核基质残余RNP网络是一种预先存在结构的分离物这一概念，并且这种内部网络的扰动可由RNA降解、必需金属离子的耗尽和蛋白水解产生。
