RESUMO
Catalase is one of the most abundant enzymes on Earth. It decomposes hydrogen peroxide, thus protecting cells from dangerous reactive oxygen species. The catalase-encoding gene is conspicuously absent from the genome of most representatives of the family Trypanosomatidae. Here, we expressed this protein from the Leishmania mexicana Β-TUBULIN locus using a novel bicistronic expression system, which relies on the 2A peptide of Teschovirus A. We demonstrated that catalase-expressing parasites are severely compromised in their ability to develop in insects, to be transmitted and to infect mice, and to cause clinical manifestation in their mammalian host. Taken together, our data support the hypothesis that the presence of catalase is not compatible with the dixenous life cycle of Leishmania, resulting in loss of this gene from the genome during the evolution of these parasites.
Assuntos
Catalase/genética , Leishmania mexicana/crescimento & desenvolvimento , Leishmania mexicana/patogenicidade , Estágios do Ciclo de Vida/genética , Proteínas de Protozoários/genética , Fatores de Virulência/genética , Animais , Catalase/metabolismo , Células Cultivadas , Feminino , Leishmania mexicana/genética , Camundongos , Camundongos Endogâmicos BALB C , Psychodidae/parasitologia , Teschovirus/genética , Virulência , Fatores de Virulência/metabolismoRESUMO
Here we report sequence and phylogenetic analysis of two new isolates of Leishmania RNA virus 2 (LRV2) found in Leishmania major isolated from human patients with cutaneous leishmaniasis in south Uzbekistan. These new virus-infected flagellates were isolated in the same region of Uzbekistan and the viral sequences differed by only nineteen SNPs, all except one being silent mutations. Therefore, we concluded that they belong to a single LRV2 species. New viruses are closely related to the LRV2-Lmj-ASKH documented in Turkmenistan in 1995, which is congruent with their shared host (L. major) and common geographical origin.