Chromosomal organisation of a repeated gene cluster expressed in mammalian stages of Leishmania.

The genomic organisation of a large Leishmania gene cluster, expressed predominantly in intracellular, infective parasite stages, has been determined. Using cosmid cloning, parasite DNA fingerprinting, partial digestion and mapping with 'end-specific' probes, the Lm cDNA2 gene array has been localised to a 55-kb ClaI fragment within the L. major genome. Six tandemly linked gene copies are transcribed to produce an abundant 6-kb transcript; the seventh and last copy of the cluster is truncated at its 3' end. It is likely that these genes encode one or more proteins specific to infective stages of the parasite life cycle.