Maisnier-Patin Sophie, Malandrin Laurence, Birkeland Nils-Kåre, Bernander Rolf
Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden.
Mol Microbiol. 2002 Sep;45(5):1443-50. doi: 10.1046/j.1365-2958.2002.03111.x.
We analysed chromosome replication patterns in the two hyperthermophilic euryarchaea Archaeoglobus fulgidus and Methanocaldococcus(Methanococcus) jannaschii by marker frequency analysis (MFA). For A. fulgidus, the central region of the chromosomal physical map displayed a higher relative abundance in gene dosage during exponential growth, with two continuous gradients to a region of lower abundance at the diametrically opposite side of the genome map. This suggests bidirectional replication of the A. fulgidus chromosome from a single origin. The organization of the putative replication origin region relative to the cdc6, mcm and DNA polymerase genes differed from that reported for Pyrococcus species. No single replication origin or termination regions could be identified for M. jannaschii, adding to the list of unusual properties of this organism. The organization of the A. fulgidus cell cycle was characterized by flow cytometry analysis of the samples from which genomic DNA was extracted for MFA. The relative lengths of the cell cycle periods were found to be similar to those of crenarchaea.
我们通过标记频率分析（MFA）对两种嗜热广古菌——嗜热栖热袍菌和詹氏甲烷球菌（原甲烷球菌）的染色体复制模式进行了分析。对于嗜热栖热袍菌，染色体物理图谱的中心区域在指数生长期间基因剂量显示出较高的相对丰度，从该区域向基因组图谱直径相对侧的较低丰度区域存在两个连续梯度。这表明嗜热栖热袍菌染色体从单一原点进行双向复制。假定的复制起点区域相对于cdc6、mcm和DNA聚合酶基因的组织方式与报道的火球菌属物种不同。詹氏甲烷球菌未鉴定出单一的复制起点或终止区域，这增加了该生物体不寻常特性的列表。通过对用于MFA提取基因组DNA的样本进行流式细胞术分析，对嗜热栖热袍菌的细胞周期组织进行了表征。发现细胞周期各时期的相对长度与泉古菌相似。
