Kiss János, Nagy Zita, Tóth Gábor, Kiss György Botond, Jakab Júlia, Chandler Michael, Olasz Ferenc
Agricultural Biotechnology Center, Szent-Györgyi Albert u. 4, H-2100, Gödöllo, Hungary.
Mol Microbiol. 2007 Mar;63(6):1731-47. doi: 10.1111/j.1365-2958.2007.05621.x.
We have analysed the transposition and target selection strategy of IS1655, a typical IS30 family member resident in Neisseria meningitidis. We have redefined IS1655 as a 1080 bp long element with 25 bp imperfect inverted repeats (IRs), which generates a 3 bp target duplication and have shown that it transposes using an intermediate with abutted IRs separated by 2 bp. IS1655 exhibits bipartite target specificity inserting preferentially either next to sequences similar to its IRs or into an unrelated but well defined sequence. IR-targeting leads to the formation of a new junction in which the targeted IR and one of the donor IRs are separated by 2 bp. The non-IR targets were characterized as an imperfect 19 bp palindrome in which the central five positions show slight GC excess and the distal region is AT-rich. Artificial targets designed according to the consensus were recognized by the element as hot spots for insertion. The organization of IS1655 is similar to that of other IS30 family members. Moreover, it shows striking similarity to IS30 in transposition strategy even though their transposases differ in their N-terminal regions, which, for IS30, appears to determine target specificity. Comparative analysis of the transposases and the evolutionary aspects of sequence variants are also briefly discussed.
我们分析了IS1655的转座和靶标选择策略，IS1655是脑膜炎奈瑟菌中典型的IS30家族成员。我们将IS1655重新定义为一个1080 bp长的元件，具有25 bp的不完全反向重复序列（IRs），它会产生3 bp的靶标重复，并已表明它通过一个中间产物进行转座，该中间产物的相邻IRs被2 bp隔开。IS1655表现出二分靶标特异性，优先插入与其IRs相似的序列旁边或插入一个不相关但定义明确的序列中。靶向IR会导致形成一个新的连接点，其中靶向的IR和供体IR之一被2 bp隔开。非IR靶标被鉴定为一个不完全的19 bp回文序列，其中中央五个位置显示出轻微的GC过量，远端区域富含AT。根据共有序列设计的人工靶标被该元件识别为插入热点。IS1655的结构与其他IS30家族成员相似。此外，尽管它们的转座酶在N端区域不同，但在转座策略上它与IS30表现出惊人的相似性，对于IS30来说，N端区域似乎决定了靶标特异性。还简要讨论了转座酶的比较分析和序列变体的进化方面。
