Takahashi Kiwamu, Sekine Yasuhiko, Chibazakura Taku, Yoshikawa Hirofumi
Department of Bioscience, Tokyo University of Agriculture, Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan.
Department of Life Science, College of Science, Rikkyo (St Paul's) University, Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan.
Microbiology (Reading). 2007 Aug;153(Pt 8):2553-2559. doi: 10.1099/mic.0.2007/007104-0.
Most of the spontaneous poly-gamma-glutamate (gamma-PGA)-deficient mutants of Bacillus subtilis (natto) appear to have resulted from the insertion of IS4Bsu1 exclusively into the comP gene. However, complete genomic analysis of B. subtilis 168, a close relative of B. subtilis (natto), revealed no IS4Bsu1 insertion. Preliminary experiments using a transformable 'natto' strain indicated that the frequency of transposition of IS4Bsu1 was exceptionally high under competence-developing conditions. On the other hand, such high-frequency transposition was not observed when cells were grown in a rich medium, such as LB medium, suggesting that there must be suitable environmental conditions that give rise to the transposition of IS4Bsu1. To assess the behaviour of IS4Bsu1 and explore any host factors playing roles in IS transposition, an intermolecular transposition assay system was constructed using a modified IS4Bsu1 element in B. subtilis 168. Here, the details of the intermolecular transposition assay system are given, and the increase in transposition frequency observed under high-temperature and competence-inducing conditions is described.
大多数枯草芽孢杆菌(纳豆芽孢杆菌)的自发多聚γ-谷氨酸(γ-PGA)缺陷型突变体似乎是由于IS4Bsu1仅插入到comP基因中所致。然而,对枯草芽孢杆菌(纳豆芽孢杆菌)的近亲枯草芽孢杆菌168进行的全基因组分析显示,没有IS4Bsu1插入。使用可转化的“纳豆”菌株进行的初步实验表明,在感受态发育条件下,IS4Bsu1的转座频率异常高。另一方面,当细胞在丰富培养基(如LB培养基)中生长时,未观察到这种高频转座,这表明一定存在适合的环境条件导致IS4Bsu1的转座。为了评估IS4Bsu1的行为并探索在IS转座中起作用的任何宿主因子,在枯草芽孢杆菌168中使用修饰的IS4Bsu1元件构建了分子间转座分析系统。在此,给出了分子间转座分析系统的详细信息,并描述了在高温和感受态诱导条件下观察到的转座频率增加情况。