Jessberger Rolf
The Carl C. Icahn Center for Gene Therapy and Molecular Medicine, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA.
IUBMB Life. 2003 Dec;55(12):643-52. doi: 10.1080/15216540310001639661.
How should a protein be designed to serve in processes as diverse as chromosome condensation, sister chromatid cohesion, DNA recombination, gene dosage regulation, and perhaps even gene silencing or transcriptional regulation--which occur in both mitosis and meiosis? Such a protein or protein complex needs to bear DNA interaction domains, it needs the capacity to use energy to move DNA, it needs to enter into highly specific protein interactions, it needs to be large enough to link two DNA molecules, it needs to be of sufficient flexibility to cope with different types of chromatin structure, yet it also needs to be rigid enough to pull, push or enclose DNA. SMC proteins fulfill these requirements and form the core units of high molecular weight complexes that act in all those processes, and are essential for some of them. SMC stands for 'Structural Maintenance of Chromosomes', although SMC proteins are not static scaffold proteins merely providing support for a particular chromosome structure. SMC proteins are rather highly dynamic actors, that generate and modulate chromosome structures, affecting a plethora of biological processes.
一种蛋白质应如何设计才能参与诸如染色体浓缩、姐妹染色单体黏连、DNA重组、基因剂量调控，甚至可能还有基因沉默或转录调控等在有丝分裂和减数分裂中都会发生的多种不同过程呢？这样一种蛋白质或蛋白质复合体需要具备DNA相互作用结构域，需要有利用能量移动DNA的能力，需要进行高度特异性的蛋白质相互作用，需要足够大以连接两个DNA分子，需要有足够的灵活性来应对不同类型的染色质结构，但同时也需要足够刚性以拉动、推动或包围DNA。SMC蛋白满足了这些要求，并形成了在所有这些过程中起作用的高分子量复合体的核心单元，且对其中一些过程至关重要。SMC代表“染色体结构维持”，尽管SMC蛋白并非仅仅为特定染色体结构提供支持的静态支架蛋白。相反，SMC蛋白是高度动态的参与者，它们生成并调节染色体结构，影响众多生物学过程。
