Cellular function and regulation of RCC1 isoforms

生物体是由细胞组成的。控制每个细胞所有功能的基因由DNA组成，并聚集在细胞核内的几条染色体中。细胞核和细胞其余部分（细胞质）之间的交流对于基因编码的蛋白质的产生是重要的。细胞核和细胞其余部分之间的相互作用可能对细胞的空间组织很重要，特别是在细胞分裂期间，当细胞核被戏剧性地重组时。在动物和植物细胞中，包围染色体的膜结构核膜在细胞分裂时破裂，成对的染色体排列成纺锤体结构。每对染色体中的一条被分离到纺锤体的两端，然后这种结构被破坏，细胞被夹成两半，留下一组染色体在每个新细胞中形成一个新的细胞核。在细胞分裂过程中，染色体和纺锤体相对于细胞其余部分的空间方向决定了细胞分裂的平面。这在组织中很重要，细胞彼此相对排列，细胞内结构呈极化，即沿特定方向排列。一种叫做Ran的蛋白质在细胞核和细胞其他部分之间的通讯中起着重要作用。Ran的活性形式是由另一种蛋白质RCC1在染色体上制造的。活性Ran指导其他蛋白质和大分子在细胞核和细胞质之间的运动。它还在有丝分裂和核膜形成过程中指导纺锤体组装。我们发现RCC1至少以三种不同的形式存在于细胞中，我们认为这些形式可能具有不同的功能，并且在细胞在发育和癌症过程中积极增殖时可能很重要。我们将研究这些不同的RCC1亚型是如何工作的，使用人类细胞和青蛙卵子的提取物，这些提取物可以在试管中复制复杂的过程，如纺锤体组装和核形成。我们将通过一种叫做质谱法的技术来研究由RCC1同种异构体形成的蛋白质复合物。我们还将使用先进的显微镜技术来研究RCC1亚型如何在培养皿中生长的活细胞中起作用。为了做到这一点，我们将在细胞中制造RCC1亚型，并将其与来自水母的天然荧光蛋白偶联。这项工作将使我们了解RCC1亚型是如何工作的，以及细胞核和细胞质之间的通信如何协调细胞中的复杂过程。这项工作可能有助于我们了解如何控制细胞分裂和组织生长，以及它们如何在疾病中出错。

Living organisms are made of cells. The genes that control all the functions of each cell are made of DNA and are collected in several chromosomes that are contained in the cell nucleus. Communication between the nucleus and the rest of the cell (the cytoplasm) is important for the production of proteins encoded by the genes. The interaction between the nucleus and the rest of the cell may be important for the spatial organisation of the cell, particularly during cell division, when the nucleus is dramatically reorganised. In animal and plant cells, the nuclear envelope, a membrane structure that surrounds the chromosomes, breaks down during cell division, and pairs of chromosomes become arranged on a structure called the spindle. One of each pair of chromosomes is separated to each end of the spindle, then this structure breaks down and the cell is pinched in two, leaving one set of chromosomes to form a new nucleus in each new cell. During cell division, the spatial orientation of the chromosomes and the spindle relative to the rest of the cell determines the plane of cell division. This is important in tissues, where cells are arranged relative to each other and their intracellular structures are polarised, that is arranged in a particular direction. A protein called Ran is important in the communication between the nucleus and the rest of the cell. The active form of Ran is made at chromosomes by another protein, RCC1. Active Ran directs the movement of other proteins and large molecules between the nucleus and cytoplasm. It also directs spindle assembly during mitosis and nuclear envelope formation. We have found that RCC1 exists in cells in at least three different forms (isoforms) that we think may have different functions and may be important when cells actively proliferate during development and in cancer. We will study how these different RCC1 isoforms work, using extracts of human cells and frog eggs which can reproduce complicated processes like spindle assembly and nuclear formation in a test tube. We will investigate the protein complexes made by RCC1 isoforms by a technique called mass spectrometry. We will also use advanced techniques for microscopy to study how RCC1 isoforms work in living cells that are grown on a Petri dish. To do this, we will make RCC1 isoforms in the cells coupled to a naturally fluorescent protein from jellyfish. This work will enable us understand how RCC1 isoforms work and how complicated processes in cells are coordinated by communication between the nucleus and cytoplasm. This work may help us to understand how to control cell division and tissue growth, and how they can go wrong in diseases.