Peters K E, Commings D E
J Cell Biol. 1980 Jul;86(1):135-55. doi: 10.1083/jcb.86.1.135.
The proteins of rat liver cytoplasm, nuclear washes, matrix, membrane, heterogeneous nuclear (hn)RNA proteins and chromatin were examined by two-dimensional gel electrophoresis. The inclusion in the gels of six common protein standards of carefully selected molecular weight and isoelectric point allowed us to clearly follow the distribution of specific proteins during nuclear extraction. In the nuclear washes and chromatin, we observed five classes of proteins: (a) Exclusively cytoplasmic proteins, present in the first saline-EDTA wash but rapidly disappearing from subsequent washes; (b) ubiquitous proteins of 75,000, 68,000, 57,000, and 43,000 mol wt, the latter being actin, found in the cytoplasm, all nuclear washes and the final chromatin pellet; (c) proteins of 94,000, 25,000, and 20,500 mol wt specific to the nuclear washes; (d) proteins present in the nuclear washes and final chromatin, represented by species at 62,000, 55,000, 54,000, and 48,000 mol wt, primarily derived from the nuclear matrix; and (e) two proteins of 68,000 mol wt present only in the final chromatin. The major 65,000-75,000-mol wt proteins seen by one-dimensional gel electrophoresis of nuclear matrix were very heterogeneous and contained a major acidic, an intermediate, and a basic group. A single 68,000-mol wt polypeptide constituted the majority of the membrane-lamina fraction, consistent with immunological studies indicating that a distinct subset of matrix proteins occurs, associated with heterochromatin, at the periphery of the nucleus. Actin was the second major nuclear membrane-lamina protein. Two polypeptides at 36,000 and 34,000 mol wt constituted 60% of the hnRNP. Approximately 80% of the mass of the nonhistone chromosomal proteins (NHP) from unwashed nuclei is contributed by nuclear matrix and hnRNPs, and essentially the same patterns were seen with chromatin NHP. The concept of NHP being a distinct set of DNA-bound proteins is unnecessarily limiting. Many are derived from the nuclear matrix or hnRNp particles and vary in the degree to which they share different intracellular compartments.
通过二维凝胶电泳对大鼠肝脏细胞质、核洗液、核基质、膜、不均一核（hn）RNA蛋白和染色质中的蛋白质进行了检测。在凝胶中加入六种精心挑选的分子量和等电点的常见蛋白质标准品，使我们能够清楚地追踪特定蛋白质在核提取过程中的分布。在核洗液和染色质中，我们观察到五类蛋白质：（a）仅存在于细胞质中的蛋白质，存在于第一次盐水 - EDTA洗液中，但在随后的洗液中迅速消失；（b）分子量为75,000、68,000、57,000和43,000的普遍存在的蛋白质，后者为肌动蛋白，存在于细胞质、所有核洗液和最终的染色质沉淀中；（c）核洗液特有的分子量为94,000、25,000和20,500的蛋白质；（d）存在于核洗液和最终染色质中的蛋白质，以分子量为62,000、55,000、54,000和48,000的蛋白质为代表，主要来源于核基质；（e）仅存在于最终染色质中的两种分子量为68,000的蛋白质。通过一维凝胶电泳在核基质中看到的主要分子量为65,000 - 75,000的蛋白质非常不均一，包含一个主要的酸性基团、一个中间基团和一个碱性基团。单一的分子量为68,000的多肽构成了膜 - 核纤层部分的大部分，这与免疫学研究一致，表明在细胞核周边与异染色质相关的核基质蛋白存在一个独特的亚群。肌动蛋白是第二大主要的核膜 - 核纤层蛋白。分子量为36,000和34,000的两种多肽构成了hnRNP的60%。未洗涤细胞核中非组蛋白染色体蛋白（NHP）约80%的质量由核基质和hnRNP贡献，染色质NHP也呈现出基本相同的模式。将NHP视为一组独特的与DNA结合的蛋白质的概念限制过多。许多NHP来源于核基质或hnRNP颗粒，并且它们在共享不同细胞内区室的程度上存在差异。
