The H locus present in the Leishmania spp. is a 40 Kb region that codes for genes involved in this pathogen's resistance to drugs and virulence. The projects conducted in our laboratory investigate the amplification phenomenon and the function of the genes contained in this locus in several species of this parasite protozoon. We have characterized the anatomy of this locus in L. braziliensis, and demonstrated that, unlike species of the subgenus Leishmania, the phenomenon of genic amplification is not favored in this species. In addition, we have identified the gene that confers resistance to terbinafine, LmYIP1, and the gene LmHUS1, possibly related to DNA repair processes in the parasite. The objectives of this proposal aim to characterize the genes contained in the H locus of Leishmania spp. More specifically, we will investigate:(i) the involvement of LmYIP1 in the parasite's vesicle traffic;(ii) the structure of the LmHUS1 gene and its involvement in the cell cycle control; and we will characterize(iii) the possible angiostatic action of the parasite's TTRS.