title: Analysis of Plasmodium falciparum var genes expressed in children from Papua New Guinea.
abstract: BACKGROUND
  The variable antigen P. falciparum erythrocyte membrane protein-1 (PfEMP1) is a major virulence factor in malaria. A large number of var genes encode PfEMP1, and we hypothesized that a restricted PfEMP1 repertoire determines clinical disease presentation. We conducted a case-control study in Papua New Guinea and analyzed transcribed var genes in naturally infected children.
  
  
  METHODS
  var messenger RNA was isolated from 78 children with asymptomatic, mild, or severe malaria. We prepared complementary DNA from the upstream region into the DBL1alpha domain and picked, on average, 20 clones for sequencing.
  
  
  RESULTS
  Twenty-five percent of centrally located var genes were shared between children, whereas only 5% of subtelomeric genes were shared, indicating lower diversity in the former group. Linkage between group B or C var upstream sequences and DBL1alpha groups was not observed, which impeded prediction by DBL1alpha analysis. A higher proportion of var group A sequences was detected in symptomatic malaria, and a subgroup of frequently encountered var genes with complex head structure seems to be associated with severe malaria. A subset of var group C genes was frequently expressed in older children with asymptomatic high levels of parasitemia.
  
  
  CONCLUSIONS
  Despite this vast diversity, restricted disease-associated var genes were identified and might be used for innovative interventions based on PfEMP1.
authors: Swiss Tropical Institute, Basel, Switzerland.
authors: Nicole
authors: N
authors: Falk
authors: Mirjam
authors: M
authors: Kaestli
authors: Weihong
authors: W
authors: Qi
authors: Michael
authors: M
authors: Ott
authors: Kay
authors: K
authors: Baea
authors: Alfred
authors: A
authors: Cortés
authors: Hans-Peter
authors: HP
authors: Beck
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016022:Case-Control Studies; D002648:Child; D005786:Gene Expression Regulation / Q000502:physiology*; D014644:Genetic Variation; D006801:Humans; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000469:parasitology*; D008969:Molecular Sequence Data; D010219:Papua New Guinea / Q000453:epidemiology; D010802:Phylogeny; D010963:Plasmodium falciparum / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D016053:RNA, Protozoan / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D015800:Protozoan Proteins; D016053:RNA, Protozoan; C085731:erythrocyte membrane protein 1, Plasmodium falciparum