Boursaux-Eude C, Saint Girons I, Zuerner R
Unité de Bactériologie Moléculaire et Médicale, Institut Pasteur, Paris, France.
Microbiology (Reading). 1995 Sep;141 ( Pt 9):2165-73. doi: 10.1099/13500872-141-9-2165.
Copies of an insertion-sequence (IS)-like element were isolated from two closely related serovars of Leptospira interrogans sensu stricto. Nucleotide sequence analysis of the 1236 bp element showed a characteristic IS structure with terminal imperfect inverted repeats (IRs) flanking a 1159 bp central region. This element was designated IS1500. Four open reading frames (orfA-orfD) were found in the central 'unique' region of IS1500. Similarities were detected between ORFA and ORFB and the putative transposases from members of the IS3 family of transposable elements. IS1500 or IS1500-like sequences were also detected in all other pathogenic leptospiral serovars, but not in the saprophytic species L. biflexa. Differences in IS1500 copy numbers in members of the same species suggest that this element can transpose. Physical mapping of IS1500 insertions in L. interrogans serovars icterohaemorrhagiae and pomona showed insertions were only on the large chromosomal replicon. The location of some IS1500 insertions coincides with regions of the genome that have undergone large rearrangements.
从问号状钩端螺旋体狭义的两个密切相关血清型中分离出类插入序列（IS）元件的拷贝。对1236 bp元件的核苷酸序列分析显示，其具有特征性的IS结构，在1159 bp的中央区域两侧有末端不完全反向重复序列（IRs）。该元件被命名为IS1500。在IS1500的中央“独特”区域发现了四个开放阅读框（orfA - orfD）。在ORFA和ORFB与来自转座元件IS3家族成员的推定转座酶之间检测到相似性。在所有其他致病性钩端螺旋体血清型中也检测到IS1500或类IS1500序列，但在腐生种双曲钩端螺旋体中未检测到。同一物种成员中IS1500拷贝数的差异表明该元件可以转座。对黄疸出血型和波摩那群问号状钩端螺旋体中IS1500插入位点的物理图谱分析表明，插入仅发生在大的染色体复制子上。一些IS1500插入位点的位置与基因组中发生了大规模重排的区域一致。
