Identification of glycoproteins targeted by Trypanosoma cruzi trans-sialidase, a virulence factor that disturbs lymphocyte glycosylation.

Trypanosoma cruzi, the agent of the American trypanosomiasis or Chagas disease, bypasses its lack of de novo synthesis of sialic acids by expressing a surface-anchored trans-sialidase. This enzyme transfers sialic acid residues from the host's sialylglycoconjugates to the parasite's galactosylglycoconjugates. In addition to carrying out a pivotal role in parasite persistence/replication within the infected mammal, the trans-sialidase is shed into the bloodstream and induces alterations in the host immune system by modifying the sialylation of the immune cells.

Stage-specific expression of Trypanosoma cruzi trans-sialidase involves highly conserved 3' untranslated regions.

trans-Sialidases (TSs) are virulence factors that allow some trypanosomatids to incorporate sialic acid from host molecules. Trypanosoma cruzi bears a complex gene family coding for TS members, which can be broadly divided into two groups: one translated in stages present in the mammalian host (trypomastigote TS, tTS) and one translated in the insect vector stages (epimastigote TS, eTS). The molecular basis underlying the expression of different, nonoverlapping sets of TS proteins in either host is poorly understood, particularly because of the lack of transcription initiation control in this organism.