title: A comparative study of the genetic diversity of the 42kDa fragment of the merozoite surface protein 1 in Plasmodium falciparum and P. vivax.
abstract: We investigated the genetic diversity of the 42kDa fragment of the merozoite surface protein 1 (MSP-1) antigen in Plasmodium falciparum and P. vivax, as well as in non-human primate malarial parasites. This fragment undergoes a proteolytic cleavage generating two fragments of 19kDa (MSP-1(19)) and 33kDa (MSP-1(33)) that are critical in erythrocyte invasion. We found that overall the MSP-1(33) fragment exhibits greater genetic diversity than the MSP-1(19) regardless of the species. We have found evidence for positive natural selection only in the human malaria parasites by comparing the rate of non-synonymous versus synonymous substitutions. In addition, we found clear differences between the two major human malaria parasites. In the case of P. falciparum, positive natural selection is acting on the MSP-1(19) region while the MSP-1(33) is neutral or under purifying selection. The opposite pattern was observed in P. vivax. Our results suggest different roles of this antigen in the host-parasite immune interaction in each of the major human malarial parasites.
authors.affiliation: School of Life Sciences, Arizona State University, P.O. Box 874501, Tempe, AZ 85287-4501, United States.
authors.forename: M Andreina
authors.initials: MA
authors.lastname: Pacheco
authors.forename: Amanda C
authors.initials: AC
authors.lastname: Poe
authors.forename: William E
authors.initials: WE
authors.lastname: Collins
authors.forename: Altaf A
authors.initials: AA
authors.lastname: Lal
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Tanabe
authors.forename: Simon K
authors.initials: SK
authors.lastname: Kariuki
authors.forename: Venkatachalam
authors.initials: V
authors.lastname: Udhayakumar
authors.forename: Ananias A
authors.initials: AA
authors.lastname: Escalante
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D014644:Genetic Variation; D006790:Host-Parasite Interactions; D020066:Merozoite Surface Protein 1 / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics; D010802:Phylogeny; D010963:Plasmodium falciparum / Q000235:genetics*; D010966:Plasmodium vivax / Q000235:genetics*; D012641:Selection, Genetic; D016415:Sequence Alignment
chemical_list: D020066:Merozoite Surface Protein 1; D010446:Peptide Fragments