Trypanosoma cruzi putative amino acid transporter genes: A post genomic analysis

SILBER, ARIEL; PEREIRA, CLAUDIO; BOUVIER, LEÓN ALBERTO; LOPEZ, C; TONELLI, R; COLLI, W; ALVES, M

Caxambú, Brazil

Congreso; XXX Annual Meeting in Basic Research in Chagas Disease. XIX, Annual Meeting of The Brazilian Society of Protozoology; 2003

The metabolism of Trypanosoma cruzi is largely based on the consumption of amino acids, mainly proline, and aspartic and glutamic acids, which are the main carbon and energy sources for several stages of the parasite life cycle. An arginine kinase that converts arginine in phosphoarginine, a phosphagen with a role as energy reservoir, was recently described. Also, the literature has established that Pro, Asp and Glu somehow participate in the T. cruzi differentiation process. The transport of amino acids into the parasite may be regarded as the first step of their metabolic pathways, making the identification of genes coding for transporters a major goal aiming at metabolic research and drug design. Notwithstanding, the mechanisms by which amino acids are transported into the cytoplasm in T. cruzi are poorly studied and, surprisingly, no protein with amino acid transport activity has been characterized, as yet, at the molecular level. In the present work, advantage has been taken from the information generated by the T. cruzi genome project in order to identify genes coding for putative amino acid transporters. Ten thousand partial sequences corresponding to ESTs and GSSs have been used to assemble CONTIGs containing 50-100 complete ORFs. The existence of such virtual ORFs was confirmed by PCR and sequencing, and the fact that they are effectively expressed were indicated by Northern blot and RT-PCR. Interestingly, some of the obtained CONTIGs contained more than one ORF coding for putative amino acid transporters. This observation raises the question whether amino acid transporter genes would be organized in clusters in the parasite.