title: Comparative transcriptomal analysis of isogenic Plasmodium falciparum clones of distinct antigenic and adhesive phenotypes.
abstract: Antigenic variation is a survival mechanism developed by the malaria parasite Plasmodium falciparum in order to allow for the establishment of a chronic infection. Here we have studied clonal differences in the transcriptomes of two isogenic P. falciparum clones (3D7S8.4 and 3D7AH1S2) of distinct adhesive and antigenic phenotypes employing a P. falciparum 70-mer oligonucleotide microarray. Fifteen transcripts were highly differentially expressed (greater than a 5-fold change) with five transcripts upregulated in 3D7AH1S2 compared to 3D7S8.4, and ten downregulated. Identified genes encode apical organellar (Gbph2, GBP-related antigen), cell cycle and DNA/RNA processing (SERA-5, RNA-methylase), cell-rescue, defense/virulence (RESA-2, RIFIN, PfEMP1) and hypothetical proteins (PFB0115w, PFI1445w, MAL13P1.121). A number of short and full-length var transcripts were differentially expressed between the clones but one full-length transcript was dominant in both rings and trophozoites (PFD0630c versus PFF0845c). Distinct members of two other variant gene families (phist-a and rif-like), scattered over the subtelomeric areas of the 14 chromosomes, were also found to be clonally and developmentally expressed. Three sibling-clones of 3D7AH1S2 (3D7AH1S1, -S3, -S4) were further studied for the expression of transcripts upregulated in 3D7AH1S2 compared to 3D7S8.4. Individual var and phist-a genes were found expressed in all of the clones while the expression of a rif-like gene and gbph2 varied in-between the clones. The present data provides evidence for complex transcriptional differences between closely related isogenic P. falciparum of distinct adhesive and antigenic characteristics.
authors.affiliation: Swedish Institute for Infectious Disease Control (SMI), SE-171 82 Stockholm, Sweden.
authors.forename: Bobo W
authors.initials: BW
authors.lastname: Mok
authors.forename: Ulf
authors.initials: U
authors.lastname: Ribacke
authors.forename: Gerhard
authors.initials: G
authors.lastname: Winter
authors.forename: Ben H
authors.initials: BH
authors.lastname: Yip
authors.forename: Chuen-Seng
authors.initials: CS
authors.lastname: Tan
authors.forename: Victor
authors.initials: V
authors.lastname: Fernandez
authors.forename: Qijun
authors.initials: Q
authors.lastname: Chen
authors.forename: Peter
authors.initials: P
authors.lastname: Nilsson
authors.forename: Mats
authors.initials: M
authors.lastname: Wahlgren
mesh_terms: D000818:Animals; D000940:Antigenic Variation; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology; D016466:CHO Cells; D002448:Cell Adhesion / Q000235:genetics*; D006224:Cricetinae; D003412:Cricetulus; D004912:Erythrocytes / Q000469:parasitology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D017125:Genes, Protozoan; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D010963:Plasmodium falciparum / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D014158:Transcription, Genetic
chemical_list: D000953:Antigens, Protozoan