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Heterogeneity of the genes encoding the major surface glycoprotein of Leishmania donovani
J R Webb1, L L Button, W R McMaster
1Department of Medical Genetics, University of British Columbia, Vancouver, Canada.
Abstract:
The major surface glycoprotein of Leishmania (GP63) is present on all known species of Leishmania and likely plays an integral role during the infection of macrophages in the mammalian host. To identify regions of GP63 which may be of functional significance, the nucleotide sequence of a gene encoding GP63 of Leishmania donovani was determined and compared to the sequences reported for GP63 genes of Leishmania major and Leishmania chagasi. The GP63 nucleotide and predicted protein sequence was highly conserved among the 3 species despite their diverse geographical distribution. L. donovani GP63 is encoded by a multigene family and the gene locus contains at least 7 tandemly repeated genes and at least 3 genes which are dispersed from the tandem array. In addition, polymerase chain reaction and Southern blot analyses demonstrated that there was size heterogeneity within the pro-peptide coding regions of the multiple GP63 genes of L. donovani and that such genes were expressed concurrently in the promastigote life stage.
Insights
The surface glycoprotein GP63 (GP63) of Leishmania is highly conserved across species and plays a key role in macrophage infection. This study details the GP63 gene family in Leishmania donovani, revealing conserved sequences and concurrent gene expression.
Area of Science:
- Parasitology
- Molecular Biology
- Genetics
Background:
- The major surface glycoprotein GP63 (GP63) is crucial for Leishmania infection of macrophages.
- GP63 is present across all Leishmania species, suggesting a vital role.
Purpose of the Study:
- To identify functionally significant regions of GP63.
- To analyze the nucleotide sequence of the GP63 gene in Leishmania donovani.
- To compare GP63 gene sequences with those from Leishmania major and Leishmania chagasi.
Main Methods:
- DNA sequencing of the Leishmania donovani GP63 gene.
- Sequence comparison with GP63 genes from L. major and L. chagasi.
- Polymerase chain reaction (PCR) and Southern blot analyses to study gene structure and expression.
Main Results:
- GP63 nucleotide and predicted protein sequences are highly conserved among L. donovani, L. major, and L. chagasi.
- Leishmania donovani GP63 is encoded by a multigene family with both tandemly repeated and dispersed genes.
- Size heterogeneity was observed in the pro-peptide coding regions of L. donovani GP63 genes.
- Multiple GP63 genes are expressed concurrently in the promastigote stage.
Conclusions:
- GP63 is a highly conserved protein essential for Leishmania pathogenesis.
- The complex GP63 gene locus in L. donovani suggests intricate regulation.
- Concurrent expression of diverse GP63 genes may contribute to parasite adaptation and virulence.