title: Structurally distinct genes for the surface protease of Leishmania mexicana are developmentally regulated.
abstract: gp63 is a highly abundant glycosylphosphatidylinositol (GPI)-anchored membrane protein expressed in both the promastigote and the amastigote forms of Leishmania species. In Leishmania mexicana, gp63 exists as a heterogeneous family of proteins that are differentially processed and localized during the 2 developmental stages. In this study we determined the molecular organization of the L. mexicana gp63 gene family, demonstrating that the gp63 genes fall into 3 linked families of tandemly repeated, but structurally distinct, entities designated as C1, C2 and C3. The C1 and C2 gene clusters contain 4-5 copies each, while the C3 gene may be single copy. Whilst promastigotes contain transcripts from all 3 gene classes, the intracellular amastigote only expresses detectable transcript from the C1 gene class. Moreover, the sequence of the C1 genes predicts a unique carboxy terminus substantially different from the GPI anchor addition signal sequence found in other Leishmania spp. and which has characteristics incompatible with substitution with a GPI anchor. These findings have significance for both the diversity of gp63 and for the regulation of tightly clustered, tandem gene arrays.
authors.affiliation: Department of Pathology, New York University Medical Center, NY.
authors.forename: E
authors.initials: E
authors.lastname: Medina-Acosta
authors.forename: R E
authors.initials: RE
authors.lastname: Karess
authors.forename: D G
authors.initials: DG
authors.lastname: Russell
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016054:DNA, Protozoan / Q000235:genetics; D005786:Gene Expression Regulation; D017125:Genes, Protozoan; D007891:Leishmania / Q000235:genetics; D007894:Leishmania mexicana / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D008666:Metalloendopeptidases / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid
chemical_list: D016054:DNA, Protozoan; D008666:Metalloendopeptidases; C055146:glycoprotein gp63, Leishmania