Klaer R, Kühn S, Tillmann E, Fritz H J, Starlinger P
Mol Gen Genet. 1981;181(2):169-75. doi: 10.1007/BF00268423.
IS-elements are devoid of easily recognizable transacting functions and exert their visible effects in the position cis only (recent reviews Calos and Miller 1980; Starlinger 1980). It has been a matter of debate, whether these elements encode functions for their own transposition. In the case of the E. coli IS-elements this could not easily be determined by genetic methods, because most of these elements are present in several copies (Saedler and Heiss 1973; Deonier et al. 1979). In the case of the IS-elements flanking transposons, evidence has recently been brought forward that these carry the transposition specificity (Rothstein et al. 1980; Kleckner 1980; Grindley 1981). IS4 is present in one copy only in several E. coli K12 strains and should, therefore, be suitable for genetic and physiological studies (Chadwell et al. 1979). It has been cloned from several sites on the E. coli chromosome in pBR322 (Klaer and Starlinger 1980). Here we report the DNA sequence of IS4 which contains an open reading frame for 442 amino acids, and of the junctions of this element with surrounding DNA at three different sites in the E. coli chromosome.
插入序列（IS元件）缺乏易于识别的反式作用功能，仅在顺式位置发挥其可见效应（近期综述见Calos和Miller，1980年；Starlinger，1980年）。这些元件是否编码自身转座的功能一直存在争议。对于大肠杆菌的IS元件，通过遗传学方法不容易确定这一点，因为这些元件大多以多个拷贝存在（Saedler和Heiss，1973年；Deonier等人，1979年）。对于位于转座子两侧的IS元件，最近有证据表明它们携带转座特异性（Rothstein等人，1980年；Kleckner，1980年；Grindley，1981年）。IS4在几种大肠杆菌K12菌株中仅以一个拷贝存在，因此应适合进行遗传学和生理学研究（Chadwell等人，1979年）。它已从大肠杆菌染色体上的几个位点克隆到pBR322中（Klaer和Starlinger，1980年）。在此我们报告IS4的DNA序列，其包含一个编码442个氨基酸的开放阅读框，以及该元件在大肠杆菌染色体三个不同位点与周围DNA的连接情况。
