Characterization of Trypanosoma cruzi TcRjl locus and analysis of its transcript

RJLs represent a recently described family of the Ras-related GTP-binding proteins. The Trypanosoma cruzi orthologue, TcRjl, was isolated and its locus was characterized in a region of almost 5 kb. Its 660 bp orf, predicting a protein of 24.13 kDa, is present as a single copy gene in T. cruzi I lineage, and from 1-2 copies in T. cruzi II lineage. TcRjl shares 73%, aa sequence similarity with its closest identified orthologue, T. brucei TbRjl. RT-PCR experiments revealed that TcRjl is transcribed in mRNA in the 3 main life forms of the parasite, while Northern hybridization demonstrated that TcRjl is transcribed in T. cruzi epimastigotes as at least 2 transcripts, one of around 950 nt and the other of 1500 nt. Splice-leader addition was mapped to a single site at -69 bp upstream of TcRjl orf indicating that the two mRNA types may derive in differences at the 3' of TcRjl mRNA. TcRjl locus presents considerable synteny with Rjl loci from Trypanosoma brucei and Leishmania major as available from their respective genome projects.