Multigene families in Trypanosoma cruzi and their role in infectivity

Abstract

The Trypanosoma cruzi genome contains the most widely expanded content (∼12,000 genes) of the trypanosomatids sequenced to date. This expansion is reflected in the high number of repetitive sequences and particularly in the large quantity of genes that make up its multigene families. Recently it was discovered that the contents of these families vary between phylogenetically unrelated strains. We review the basic characteristics of trans-sialidases and mucins as part of the mechanisms of immune evasion of T. cruzi and as ligands and factors involved in the cross talk between the host cell and the parasite. We also show recently published data describing two new multigene families, DGF-1 and MASP, that form an important part of the scenario representing the complex biology of T. cruzi.

Fig 1

Schematic representation of the diversity of gene dosage in multigene families in strains belonging to different DTUs. Shown are the different factors involved in the genetic variability observed; in the center is a schematic representation of the variations in the gene contents of multigene families in various strains of T. cruzi. The colored horizontal bars represent the gene numbers of the multigene families in each lineage. *, Silvio X10/1 (DTU I) genome sequence available; **, CL-Brener (DTU VI) genome sequence available.

Fig 2

Cell pathway of MASP synthesis. Shown are the basic composition of the mRNA and the structures of the immature and mature forms of the protein (top), with the conserved and HV regions indicated. At the top are the mature protein regions at the membrane of T. cruzi without the conserved signal peptide (SP) and C-terminal regions (processed at the Golgi apparatus and endoplasmic reticulum). On the left are two immunofluorescence images of the MASPs (obtained with anti-SP antibodies) and the surface location of HV MASP regions (obtained with antibodies against the anticatalytic region of the MASP52 protein). N, nucleus; K, kinetoplast; SL, spliced leader.