A Salanti

A Scherf

Ali Salanti

AR Berendt

ATR Jensen

CF Ockenhouse

CH Ricke

David E Arnot

DD Roberts

DI Baruch

EG Dembo

F Paul

G Winter

HM Taylor

JD Smith

JG Waterkeyn

JP Gardner

K Marsh

L Gannoun-Zaki

Lars Hviid

M Frank

M Fried

Madeleine Dahlbäck

MF Duffy

MF Ofori

MJ Gardner

Morten A Nielsen

MT Duraisingh

N Kriek

PA Magistrado

PC Bull

PE Duffy

PH David

QJ Chen

R Dzikowski

R Noviyanti

RJ Howard

S Kyes

SA Kyes

SA Ralph

SM Kraemer

T Lavstsen

T Staalsoe

Thomas Lavstsen

Thor G Theander

TS Voss

W Trager

XZ Su

Malaria Journal

English

PubMed

The var multigene family encodes PfEMP1, which are expressed on the surface of infected erythrocytes and bind to various host endothelial receptors. Antigenic variation of PfEMP1 plays a key role in malaria pathogenesis, a process partially controlled at the level of var gene transcription. Transcriptional levels, throughout the intra-erythrocytic cycle, of 59 var genes of the NF54 clone were measured simultaneously by quantitative real-time PCR. The timing of var transcript abundance, the number of genes transcribed and whether transcripts were correctly spliced for protein expression were determined. Two parasite populations were studied; an unselected population of NF54 and a selected population, NF54VAR2CSA, to compare both the transcription of var2csa and the expression pattern of the corresponding protein

Dahlbäck, Madeleine

Lavstsen, Thomas

Salanti, Ali

Hviid, Lars

Arnot, David E

Theander, Thor G

Nielsen, Morten A

Edinburgh Research Explorer

Changes in var gene mRNA levels during erythrocytic development in two phenotypically distinct Plasmodium falciparum parasites

Crossref

Udgivelsesdato: 2007-nullBACKGROUND: The var multigene family encodes PfEMP1, which are expressed on the surface of infected erythrocytes and bind to various host endothelial receptors. Antigenic variation of PfEMP1 plays a key role in malaria pathogenesis, a process partially controlled at the level of var gene transcription. Transcriptional levels, throughout the intra-erythrocytic cycle, of 59 var genes of the NF54 clone were measured simultaneously by quantitative real-time PCR. The timing of var transcript abundance, the number of genes transcribed and whether transcripts were correctly spliced for protein expression were determined. Two parasite populations were studied; an unselected population of NF54 and a selected population, NF54VAR2CSA, to compare both the transcription of var2csa and the expression pattern of the corresponding protein. METHODS: Synchronized parasites were harvested at different time points along the 48 hours intra-erythrocytic cycle for extraction of RNA and for analysis of expression of variant surface antigens by flow cytometry. Total RNA from each parasite sample was extracted and cDNA synthesized. Quantitative real-time PCR was performed using gene-specific primers for all var genes. Samples for flow cytometry were labelled with rabbit IgG targeting DBL5epsilon of VAR2CSA and serum IgG from malaria-exposed men and pregnant women. RESULTS: var transcripts were detected at all time points of the intra-erythrocytic cycle by quantitative real-time PCR, although transcription peaked in ring-stage parasites. There was no difference in the timing of appearance of group A, B or C transcripts, and dominant and subdominant var transcripts appeared to be correctly spliced at all time points. VAR2CSA appeared on the surface of infected erythrocytes 16 hours after invasion, consistent with previous studies of other PfEMP1. Transcription of the pseudogene var1csa could not be detected in NF54VAR2CSA cells. CONCLUSION: The optimal sampling point for analysis of var transcripts using quantitative real-time PCR is the ring-stage, which is encouraging for the analysis of fresh clinical isolates. The data presented here indicate that there is no promiscuous transcription of var genes at the individual cell level and that it is possible to correlate dominant transcripts with adhesion phenotype and clinical markers of malaria severity

Copenhagen University Research Information System

Changes in <em>var</em> gene mRNA levels during erythrocytic development in two phenotypically distinct <em>Plasmodium falciparum</em> parasites

Springer - Publisher Connector

Changes in  gene mRNA levels during erythrocytic development in two phenotypically distinct  parasites

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http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1904452

Changes in var gene mRNA levels during erythrocytic development in two phenotypically distinct Plasmodium falciparum parasites

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Springer - Publisher Connector