Institute of Protein Biochemistry, Consiglio Nazionale delle Ricerche, Via P. Castellino 111, 80131 Naples, Italy.
Biochem Soc Trans. 2011 Jan;39(1):58-63. doi: 10.1042/BST0390058.
DNA supercoiling plays essential role in maintaining proper chromosome structure, as well as the equilibrium between genome dynamics and stability under specific physicochemical and physiological conditions. In mesophilic organisms, DNA is negatively supercoiled and, until recently, positive supercoiling was considered a peculiar mark of (hyper)thermophilic archaea needed to survive high temperatures. However, several lines of evidence suggest that negative and positive supercoiling might coexist in both (hyper)thermophilic and mesophilic organisms, raising the possibility that positive supercoiling might serve as a regulator of various cellular events, such as chromosome condensation, gene expression, mitosis, sister chromatid cohesion, centromere identity and telomere homoeostasis.
DNA 超螺旋在维持染色体结构的完整性以及在特定理化和生理条件下基因组动力学和稳定性之间的平衡方面发挥着至关重要的作用。在嗜中温生物中，DNA 是负超螺旋的，直到最近，正超螺旋才被认为是（超）嗜热古菌的一个特殊标志，这些古菌需要正超螺旋来适应高温。然而，有几条证据表明，无论是在（超）嗜热生物还是嗜中温生物中，负超螺旋和正超螺旋都可能同时存在，这增加了正超螺旋可能作为各种细胞事件的调节剂的可能性，如染色体浓缩、基因表达、有丝分裂、姐妹染色单体黏合、着丝粒身份和端粒同源性。
