Molecuar Analysis of Peroxidoxin Genes from Leishmania Aethiopica
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Date
2004-06
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Addis Ababa Universty
Abstract
Cutaneous leishmaniasis in Ethiopia is primarily caused by Leishmania aethiopica and rarely
by L. tropica and L. major. There is no rapid differential diagnostic method for these species.
The intracellular survival mechanism of Leishmania parasites is not well understood although
one of the mechanisms may be production of antioxidant enzymes such as peroxidoxins.
Peroxidoxin genes have been isolated from various Leishmania species but not from
L. aethiopica. Our objective was to identify and characterize peroxidoxin genes from
L. aethiopica.
In this study, we identified two peroxidoxin genes (pxnl and Pxn2) from L. aethiopica by
PCR. Sequence analysis of the two genes showed that there is a high nucleotide sequence
homology between L. aetlziopica and other Leishmania species. Southern blot hybridization
analysis showed peroxidoxins of L. aetlziopica genes exist as multigene family. RT-PCR
demonstrated that pxnl is predominantly expressed in amastigotes and stationary phase
promastigotes, suggesting its importance for infectivity and intracellular survival. Pxn2 is
constitutively expressed in the different stages of the parasite. Northern blot analysis and
RT-PCR showed that the overall expression of all peroxidoxin genes in L. aethiopica is
higher in the amastigotes than in the promastigotes, suggesting that peroxidoxins are
impoliant for intracellular survival. Peroxidoxin genes appear to be important virulence
factors and thus may be potential targets for drug development against leishmaniasis.The
genes can be explored further as potential candidate vaccines and molecular diagnostic tools.
We suggest that further research be conducted on peroxidoxins to evaluate their potential as
diagnostics, vaccine candidates and drug targets.
Key words: Intracellular survival, L. aethiopica, peroxidoxin genes
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Keywords
Intracellular survival, L. aethiopica, Peroxidoxin genes