[Transposon Tn5 and its derivatives effectively transpose over a broad temperature range].

It was shown that the 1st class composite transposon Tn5 (5.8 Kb) and its synthetic derivatives--TnV (Tn5-ReppSC101; 6.1 Kb) and Tn5-MobRP4 (about 7.7 Kb) transpose in Escherichia coli K-12 cells (RecA strain HB101) with similar efficiency both at 28 and at 42 degrees C as well as at 37 degrees C. This property of Tn5-like elements distinguishes them from the class II transposons (such as Tn3, Tn21 etc.), whose transposition, as is well known, is strongly suppressed even at 37 degrees C. It was also demonstrated that transposition frequency of Tn5-derived elements depends on their copy number.