Heterogeneous genetic diversity pattern in Plasmodium vivax genes encoding merozoite surface proteins (MSP) -7E, -7F and -7L

Malar J. 2014 Dec 13;13:495. doi: 10.1186/1475-2875-13-495.

Abstract

Background: The msp-7 gene has become differentially expanded in the Plasmodium genus; Plasmodium vivax has the highest copy number of this gene, several of which encode antigenic proteins in merozoites.

Methods: DNA sequences from thirty-six Colombian clinical isolates from P. vivax (pv) msp-7E, -7F and -7L genes were analysed for characterizing and studying the genetic diversity of these pvmsp-7 members which are expressed during the intra-erythrocyte stage; natural selection signals producing the variation pattern so observed were evaluated.

Results: The pvmsp-7E gene was highly polymorphic compared to pvmsp-7F and pvmsp-7L which were seen to have limited genetic diversity; pvmsp-7E polymorphism was seen to have been maintained by different types of positive selection. Even though these copies seemed to be species-specific duplications, a search in the Plasmodium cynomolgi genome (P. vivax sister taxon) showed that both species shared the whole msp-7 repertoire. This led to exploring the long-term effect of natural selection by comparing the orthologous sequences which led to finding signatures for lineage-specific positive selection.

Conclusions: The results confirmed that the P. vivax msp-7 family has a heterogeneous genetic diversity pattern; some members are highly conserved whilst others are highly diverse. The results suggested that the 3'-end of these genes encode MSP-7 proteins' functional region whilst the central region of pvmsp-7E has evolved rapidly. The lineage-specific positive selection signals found suggested that mutations occurring in msp-7s genes during host switch may have succeeded in adapting the ancestral P. vivax parasite population to humans.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cluster Analysis
  • Colombia
  • DNA, Protozoan / chemistry
  • DNA, Protozoan / genetics
  • Genetic Variation*
  • Humans
  • Malaria, Vivax / parasitology
  • Membrane Proteins / genetics*
  • Merozoites*
  • Molecular Sequence Data
  • Phylogeny
  • Plasmodium vivax / genetics*
  • Plasmodium vivax / isolation & purification
  • Protozoan Proteins / genetics*
  • Sequence Analysis, DNA
  • Sequence Homology

Substances

  • DNA, Protozoan
  • Membrane Proteins
  • Protozoan Proteins
  • merozoite surface protein 7, Plasmodium

Associated data

  • GENBANK/KM212276
  • GENBANK/KM212277
  • GENBANK/KM212278
  • GENBANK/KM212279
  • GENBANK/KM212280
  • GENBANK/KM212281
  • GENBANK/KM212282
  • GENBANK/KM212283
  • GENBANK/KM212284
  • GENBANK/KM212285
  • GENBANK/KM212286
  • GENBANK/KM212287
  • GENBANK/KM212288
  • GENBANK/KM212289
  • GENBANK/KM212290
  • GENBANK/KM212291
  • GENBANK/KM212292
  • GENBANK/KM212293
  • GENBANK/KM212294
  • GENBANK/KM212295
  • GENBANK/KM212296
  • GENBANK/KM212297
  • GENBANK/KM212298
  • GENBANK/KM212299
  • GENBANK/KM212300
  • GENBANK/KM212301
  • GENBANK/KM212302