The large diverse gene family var encodes proteins involved in cytoadherence and antigenic variation of Plasmodium falciparum-infected erythrocytes.
The human malaria parasite Plasmodium falciparum evades host immunity by varying the antigenic and adhesive character of infected erythrocytes. We describe a large and extremely diverse family of P. falciparum genes (var) that encode 200-350 kDa proteins having the expected properties of antigenically variant adhesion molecules. Predicted amino acid sequences of var genes show a variable extracellular segment with domains having receptor-binding features, a transmembrane sequence, and a terminal segment that is a probable submembrane anchor. There are 50-150 var genes on multiple parasite chromosomes, and some are in clustered arrangements. var probes detect two classes of transcripts in steady-state RNA: 7-9 kb var transcripts, and an unusual family of 1.8-2.4 kb transcripts that may be involved in expression or rearrangements of var genes.
Su
X Z
XZ
Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
Heatwole
V M
VM
Wertheimer
S P
SP
Guinet
F
F
Herrfeldt
J A
JA
Peterson
D S
DS
Ravetch
J A
JA
Wellems
T E
TE
D000595:Amino Acid Sequence; D000818:Animals; D000940:Antigenic Variation / Q000235:genetics*; D000953:Antigens, Protozoan / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D015815:Cell Adhesion Molecules / Q000235:genetics*; D004912:Erythrocytes / Q000469:parasitology*; D015321:Gene Rearrangement; D017125:Genes, Protozoan / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D010963:Plasmodium falciparum / Q000235:genetics* / Q000276:immunology; D012150:Polymorphism, Restriction Fragment Length; D012333:RNA, Messenger / Q000032:analysis; D016053:RNA, Protozoan / Q000032:analysis; D015183:Restriction Mapping; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D000953:Antigens, Protozoan; D015815:Cell Adhesion Molecules; D012333:RNA, Messenger; D016053:RNA, Protozoan