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Targeted disruption of Plasmodium falciparum cysteine protease, falcipain 1, reduces oocyst production, not erythrocytic stage growth
Author(s) -
Eksi Saliha,
Czesny Beata,
Greenbaum Doron C.,
Bogyo Matthew,
Williamson Kim C.
Publication year - 2004
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2004.04108.x
Subject(s) - biology , gametocyte , proteases , plasmodium falciparum , parasite hosting , cysteine protease , malaria , virology , rna interference , gene , genetics , microbiology and biotechnology , enzyme , immunology , rna , biochemistry , world wide web , computer science
Summary Cysteine proteases are currently targets for drug development in a number of parasitic diseases, including malaria. In Plasmodium falciparum , the parasite responsible for the most virulent form of human malaria, there are four members of the cathepsin L‐like family of cysteine proteases. Three of these (falcipains 2A, 2B and 3) are thought to be primarily involved in haemoglobin digestion, whereas falcipain 1 has recently been linked to erythrocyte invasion. Neither their expression nor their role in P. falciparum gametocytogenesis, which is required for malaria transmission, has been evaluated. In this study, RNA transcripts for the falcipain family members were identified as the parasite developed through all five stages of gametocytogenesis. Falcipain 1 transcript was upregulated in gametocytes, while levels of falcipain 2A/2B decreased in late‐stage gametocytes and gametes. To evaluate the function of falcipain 1, the gene was disrupted, and clones from independent transformations were isolated. The asexual growth of the falcipain 1 minus clones was not overtly affected, and they produced morphologically normal gametocytes and gametes. However, when falcipain 1 minus parasites were fed to a mosquito, oocyst production was reduced by 70–90%, suggesting an important role for falcipain 1 during parasite development in the mosquito midgut.