Abstract.
A comparative analysis of 40 Trypanosoma cruzi L1Tc elements showed that the 2A self-cleaving sequence described in viruses is present in them. Of these elements, 72% maintain the canonical 2A motif (DxExNPGP). A high percentage has a conserved point mutation within the motif that has not been previously described. In vitro and in vivo expression of reporter polyproteins showed that the L1Tc2A sequence is functional. Mutations within certain L1Tc2A sequences affect the efficiency of the cleavage. The data indicate that the L1Tc2A sequence may be influencing the L1Tc enzymatic machinery determining the composition and level of the translated products. The residues located immediately upstream of the 2A consensus sequence increase the cleaving efficiency and appear to stabilize the relative amount of translated products.
Keywords. Self-cleaving 2A sequence, L1Tc, LINE, retrotransposon, Trypanosoma cruzi, translational regulation, picornavirus
Footnotes
These authors contributed equally to this work.
Received 26 January 2006; received after revision 11 April 2006; accepted 21 April 2006