Structural Analysis of Tn5

Excerpt

Transposon Tn5 is a movable DNA element of about 5.3 kbp that carries resistance to the aminoglycoside antibiotics kanamycin (Km) and neomycin (Nm) (Berg et al. 1975) and that also seems to encode proteins that participate in the transposition reaction (Rothstein et al. 1980). Tn5 has two 1.5-kb terminal inverted-repeat (IR) sequences that flank a central unique region of about 2.3 kb. From an evolutionary point of view, this structure can be envisaged to have evolved from two identical insertion sequence (IS) elements that were originally able to move independently but that lost this ability after fusing with the resistance gene to give rise to a larger transposable unit. To obtain more insight into its structural organization and to understand the rules governing the recombinational events that lead to integration and loss of the transposon, we have analyzed the structure of Tn5, in particular the inverted repeats, and the adjacent...