UBC Theses and Dissertations
Structure and expression of GP63 genes in Leishmania major Voth, Bevan Raymond
Leishmania are protozoan pathogens responsible for the human disease known as leishmaniasis. Leishmania parasites alternate between an insect promastigote stage and an amastigote stage found in infected macrophage cells of mammalian hosts. The major surface protein found on promastigotes is a glycoprotein with a molecular weight of 63 kDa and is referred to as GP63. Restriction map analysis of genes encoding GP63 in Leishmania major indicate that GP63 is encoded by five conserved tandemly repeated genes and a less conserved sixth gene separated from the five repeats. In this study, DNA sequence analysis of the sixth gene of the L. major gp63 locus indicated that this gene encodes a different form of GP63 with an extended carboxy terminus in comparison to GP63 encoded by gene one¹. Northern blot analysis of gp63 expression in L. major demonstrated that L. major gp63-1 is expressed in the promastigote stage whereas L. major gp63-6 is expressed in both the promastigote and intracellular amastigote stage. Furthermore, L. donovani promastigotes transfected with L. major gp63-6 were shown to express GP63 as a surface protein in FACScan analysis using an L. major specific anti-GP63 antibody suggesting that L. major GP63-6 is expressed as surface protein in promastigotes. [Footnote] ‘L. major gp63 gene 6 will be referred to as L. major gp63-6 hereafter with lowercase italicized gp63-6 representing the DNA. Uppercase unitalicized GP63-6 will refer to the protein. Likewise, L. major gp63 gene 1 will be referred to as L. major gp63-1 while the protein will be represented by L. major GP63-1.
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