the ple2scx vector was developed for the stable expression of exogenous genes in the protozoan parasite leishmania. the ple2scx construct contains three independent selection markers: herpes simplex virus thymidine kinase (hsv-tk), cytosine deaminase (cd) and streptothericin acetyltransferase gene (sat) in multiple cloning site, flanking by 5’ and 3’ untranslated regions of the previously clone...