Broad analysis reveals a consistent pattern of var gene transcription in Plasmodium falciparum repeatedly selected for a defined adhesion phenotype.
Transcription of the majority of the members of the Plasmodium falciparum var multigene family were analysed in two isolates by a quantitative approach. Both of these isolates had been repeatedly selected for adhesion to chondroitin sulphate A (CSA) and one had also been selected for adhesion to hyaluronic acid (HA). These adhesion phenotypes are expressed by many parasites isolated from placentae and are associated with malaria disease in pregnancy. Increased transcription of the var gene var2csa, or its homologue IT4 var4, was associated with the CSA and HA adhesion phenotypes in all parasites suggesting that it was the dominant, if not the only, var gene that encoded adhesion to CSA in these allogeneic isolates. Some var genes were consistently transcribed at higher levels than others regardless of expressed adhesion phenotypes suggesting a transcriptional hierarchy. Unspliced or partial transcripts were detected for most var genes tested. These atypical var gene transcripts may have implications for the regulation of var gene transcription.
Duffy
Michael F
MF
Department of Medicine, University of Melbourne, Royal Melbourne Hospital, Parkville, Victoria, Australia. mduffy@unimelb.edu.au
Byrne
Timothy J
TJ
Elliott
Salenna R
SR
Wilson
Danny W
DW
Rogerson
Stephen J
SJ
Beeson
James G
JG
Noviyanti
Rintis
R
Brown
Graham V
GV
D017398:Alternative Splicing; D000818:Animals; D002417:Cattle; D002448:Cell Adhesion; D002809:Chondroitin Sulfates / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D005799:Genes, Dominant; D014644:Genetic Variation; D006820:Hyaluronic Acid / Q000378:metabolism; D016778:Malaria, Falciparum / Q000469:parasitology; D005810:Multigene Family; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D010641:Phenotype; D010920:Placenta / Q000469:parasitology; D010963:Plasmodium falciparum / Q000166:cytology* / Q000235:genetics*; D011247:Pregnancy; D015800:Protozoan Proteins / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014158:Transcription, Genetic
D015800:Protozoan Proteins; C085731:erythrocyte membrane protein 1, Plasmodium falciparum; D006820:Hyaluronic Acid; D002809:Chondroitin Sulfates