DNA binding activities of the Herves transposase from the mosquito Anopheles gambiae

We identified the specific DNA-binding sites of the Herves transposase. Active Herves transposase was purified using an Escherichia coli expression system and bound in a site-specific manner to the subterminal and terminal sequences of the left and right ends of the element, respectively, and also interacted with the right but not the left terminal inverted repeat. We identified a common subterminal DNA-binding motif (CG/AATTCAT) that is critical and sufficient for Herves transposase binding.The Herves transposase binds specifically to a short motif located at both ends of the transposon but shows differential binding with respect to the left and right terminal inverted repeats. Despite similarities in the overall structures of hAT transposases, the regions to which they bind in their respective transposons differ in sequence ensuring the specificity of these enzymes to their respective transposon. The asymmetry with which the Herves terminal inverted repeats are bound by the transposase may indicate that these differ in their interactions with the enzyme.Transposable elements (TEs) are ubiquitous components of genomes in which they impact genomic evolution and maintenance [1-6]. Their mobility properties have resulted in their adoption as genetic tools in modern genetics with one of their many uses in biotechnology being the introduction of foreign genes into insect disease vectors of medical and agricultural importance [7-14]. Anopheles gambiae is the principal vector of the malaria-causing parasite Plasmodium falciparum in sub-equatorial Africa and is a mosquito species in which robust TE-based genetic tools need to be developed. At present there are six reports of successful genetic transformation of this mosquito, one using the P element, and five using the piggyBac element, transformation remaining a low frequency event [9,15-19]. Isolating active, well adapted, endogenous TEs from A gambiae and understanding their biology is likely to improve the efficiency o