Cloning Of Novel Protective Candidate Antigen Genes Of Malaria Parasite Plasmodium Falciparum By Mining The Malarial Genomic Database

Malaria is one of the most dangerous infectious diseases with approximately 300 million to 500 million cases of infection yearly resulting in approximately 2 million deaths. Of the four species that cause malaria in humans, P. falciparum is the greatest cause of morbidity and mortality. The development of a safe and effective intra-erythrocytic stage vaccine against P. falciparum remains a major public health objective. However, progress towards a human malaria vaccine has been slow, largely due to a lack of extensive antigens that induce protective immunity in population. To identify and characterize novel protective antigens of P. falciparum will increase our ability to develop the most effective and extensive malaria vaccine. In 1996, malaria genomic project was performed, which became the milestone of malaria research. It should be of value in development of new malaria vaccine. Our research strategy was to analyze the malaria genomic database with the bioinformatic software to look for the new protective antigen genes in two ways.The first way was to look for the proteins that contained the conserved functional motif from the second phage database (contig) of malaria genome. The dynamin gene was selected as the research object. Dynamin is a high molecular weight GTP-binding protein with an intrinsic GTPase activity. There are multiple dynamins in most species ranging from yeast to mammals. These proteins regulate clathrin-mediated endocytic transport at the plasma membrane in mammal cell, vesicle sorting and trafficking at the cellular sites other than the plasma membrane in yeast cell and vesicle-mediated cell division plate formation in plant cells. In this study, we have identified a novel dynamin-like GTPase, Pfdyn, from asexual-stage P. falciparum Dd2 cDNA library. By tBLASTn searching the NCBI malaria genomic database with the conserved sequence of the first GTP-binding domain of the yeast Vps1p protein, a 200bp probe was designed to screen the cDNA library. Pfdyn cDNA was then isolated.