The form of chromosomal DNA molecules in bacterial cells
The form of chromosomal DNA molecules in bacterial cells
复制标题
DOI：
10.1016/s0300-9084(00)01209-8
复制
发表时间：
2001-02-01
期刊：
影响因子：
3.9
通讯作者：
Bendich, AJ
中科院分区：
文献类型：
--
作者：
Bendich, AJ
细菌染色体的圆形概念最初是基于涉及DNA的共轭作图和放射自显影成像的实验。这一观点随后得到了DNA片段作图、基因组测序和染色体DNA单次切割产生的线性DNA分析的支持。环状染色体还表明存在一种分离二聚体染色体的机制，这种机制是由复制端两侧的DNA的重组和复制产生的。环状性的证据在这里进行了审查，并发现无论是圆形或线性染色体DNA分子兼容。乙锭染色DNA的移动图像显示，大多数染色体DNA呈玫瑰花结状，从密集的节点发出环状物，或呈缺乏节点的链网。这一描述适用于大肠杆菌、农杆菌、努力焦球菌、霍乱弧菌，以及lividans链霉菌的线性定位染色体及其圆形定位衍生物。在两个线性映射的疏螺旋体物种中发现了没有节点的网络。对于大肠杆菌染色体，各种大小的开环只在极低的频率被发现。在recA突变体中，通过核糖核酸酶、拓扑异构酶IV、1m NaCl或溶菌酶处理，莲座结减小或消除。提出了一种细菌染色体的模型，其中DNA由在每个染色体复制周期中多次发生的DNA损伤修复过程中产生的许多链结合点（包括重组连接，缠结和结）紧密相连。(C) 2001法国生物化学和生物分子学会/ Elsevier SAS科学和医学版。
The circular concept of the bacterial chromosome was based initially on experiments involving conjugation mapping and autoradiographic imaging of DNA. This View was then supported by DNA fragment mapping, genome sequencing, and the analysis of linear DNA produced by a single cleavage of chromosomal DNA. A circular chromosome is also indicated by the existence of a mechanism for segregating dimeric chromosomes produced by recombination and the replication of DNA on both sides of the replication terminus. The evidence for circularity is reviewed here and found to be compatible with either a circular or a linear chromosomal DNA molecule. Moving pictures of ethidium-stained DNA revealed most chromosomal DNA as a rosette form with loops emanating from a dense node or as a network of strands lacking a node. This description applies to Escherichia coli, Agrobacterium tumefaciens, Pyrococcus endeavorii, Vibrio cholerae, and both the linear-mapping chromosome of Streptomyces lividans and its circular-mapping derivative. Networks without nodes were found for two linear-mapping Borrelia species. For the E. coli chromosome, open-form circles of Various sizes were found only at extremely low frequency. The node of the rosette was reduced in size or eliminated in recA mutants, as well as by treatment with either ribonuclease, topoisomerase IV, 1 M NaCl, or lysozyme. A model is presented for the bacterial chromosome in which the DNA is compacted by many points of strand association (including recombination junctions, tangles and knots) created during the repair of DNA damage that occurs many times in each chromosome replication cycle. (C) 2001 Societe francaise de biochimie et biologie moleculaire / Editions scientifiques et medicales Elsevier SAS.