PLASTICITY OF GP63 GENE ORGANIZATION IN LEISHMANIA (VIANNIA) BRAZILIENSIS AND LEISHMANIA (VIANNIA) PERUVIANA

The genomic organization of gp63 genes in 4 and 7 isolates of Leishman ia braziliensis and L. peruviana, respectively was studied by RFLP ana lysis with 3 restriction enzymes (Bgl I, Sal I and Apa I). Our results showed a marked polymorphism among isolates. Some characters were spe cific to L. braziliensis or to L. peruviana, and others specific to th e respective biogeographical populations of L. peruviana. The average minimum copy number of gp63 genes was found to be higher in L. brazili ensis (71) than in L. peruviana (46), suggesting that deletion of gp63 genes might be partially involved in the size decrease of the chromos ome bearing gp63 genes, observed between those 2 species (from 700 to 610 kb). Our results may suggest the existence of at least 2 arrays of heterologous gp63 repeats, varying in relative copy number between L. braziliensis and L. peruviana, and among isolates of the latter speci es. Rearrangement of the gp63 genes was observed during long-term in v itro maintenance of a reference strain of L. braziliensis. These obser vations document the existence of a dynamic gp63 gene organization in Leishmania of the braziliensis complex.