Selection of endogenous reference genes for gene expression analysis in Leishmania major developmental stages.

At the era of post-genomics, gene expression analysis constitutes an important step for understanding the biological functions of genes. For this, reverse transcription and real-time polymerase chain reaction (RT-PCR) is one of the most accurate techniques available to date. Normalization with a proper internal control is critical for the generation of reliable results with biological significance. This is particularly true for pathogens, like Leishmania (L.) parasites, that alternate between different stages during their life cycle. In this study, we evaluate six different sequences for their potential as suitable internal control for the study of gene expression in three different developmental stages (procyclic and metacyclic promastigotes and amastigotes) of the parasite Leishmania major. Experiments were performed on RNA purified from three L. major isolates using the RT-PCR technique. Data analysis was performed using GeNorm and NormFinder programs. We could determine that a sequence encoding rRNA45 is the most stable in the three developmental stages of the parasite and can thus be used as a reference gene in gene expression studies in L. major.