Résumé
Strategies to construct the physical map of the Trypanosoma cruzi nuclear genome have to capitalize on three main advantage of the parasite genome, namely (a) its small size, (b) the fact that all chromosomes can be defined, and many of them can be isolated by pulse field gel electrophoresis, and (c) the fact that simple Southern blots of electrophoretic karyotypes can be used to map sequence tagged sites and expressed sequence tags to chromosomal bands. A major drawback to cope with is the complexity of T. cruzi genetics, that hinders the construction of a comprehensive genetic map. As a first step towards physical mapping, we report the construction and partial characterization of a T. cruzi CL-Brener genomic library in yeast artificial chromosomes (YACs) that consists of 2.770 individual YACs with a mean insert size of 365 kb encompassing around 10 genomic equivalents. Two libraries in bacterial artificial chromosomes (BACs) have been constructed, BACI and BACII. Both libraries represent about three genome equivalents. A third BAC library (BAC III) is being constructed. YACs and BACs are invaluable tools for physical mapping. More generally, they have to be considered as a common resource for research in Chagas disease.
Sujets)
Animaux , Cartographie chromosomique , Génome de protozoaire , Trypanosoma cruzi/génétique , Chromosomes artificiels de levure , Clones cellulaires , Sites étiquetés par des séquencesRésumé
Molecular expression cloning techniques revealed that patients with the severest clinical form of Chagas disease, chronic Chagas heart disease, presented a strong humoral response against the cloned C-terminal portion of a Trypanosoma cruzi ribosomal P protein. Parasite P antigens identification led to characterize the ribosomal P protein system in T. cruzi. Their exposed location on the ribosome, and the ®amplification® of their parasite specific, serine free C-terminal domain, generate a strong parasite specific anti-P response, that in certain cases may induce anti-P autoimmunity