RESUMEN
In our previous work we established a T7 polymerase-driven Tetracycline-inducible protein expression system in Leishmania mexicana (Biagi, 1953). We used this system to analyse gene expression profiles during development of L. mexicana in procyclic and metacyclic promastigotes and amastigotes. The transcription of the gene of interest and the T7 polymerase genes was significantly reduced upon cell differentiation. This regulation is not locus-specific. It depends on untranslated regions flanking open reading frames of the genes analysed. In this paper, we report that the previously established conventional inducible protein expression system may not be suitable for studies on differentiation of species of Leishmania Ross, 1903 and protein expression systems might have certain limitations.