DIVERSITY IN REPEAT-CONTAINING SURFACE-PROTEINS OF LEISHMANIA-MAJOR

The gene B protein (GBP) is one of the products of the LmcDNA16 gene f amily, a cluster of related but non-identical genes that are different ially-expressed during the Leishmania life cycle. This protein, which is found on the surface of infective stage parasites, contains an exte nsive region of proline-rich amino acid repeats, constituting 45% of t he total protein. The structure and stability of these repeats have be en investigated in a number of L. major strains by polymerase chain re action (PCR) amplification and Southern blotting. Data reported in thi s paper demonstrate variability between strains with respect to the nu mber of repeats encoded by GBP, although those strains isolated within adjacent geographical regions have conserved repeat structures. The d ata also reveal that some parasite lines have additional repeat sequen ces within a second, related gene in the LmcDNA16 array. Western blott ing experiments have established that these sequences are expressed in vivo, indicating that L. major strains are heterogeneous in their sur face complement of gene B repeat-containing proteins. (C) 1997 Elsevie r Science B.V.