The effect of Plasmodium falciparum Sir2a histone deacetylase on clonal and longitudinal variation in expression of the var family of virulence genes. Academic Article uri icon

Overview

MeSH

  • Animals
  • Cells, Cultured
  • Erythrocytes
  • Flow Cytometry
  • Gene Silencing
  • Histone Deacetylases
  • Humans
  • Malaria, Falciparum
  • Reverse Transcriptase Polymerase Chain Reaction
  • Virulence

MeSH Major

  • Antigenic Variation
  • Gene Expression Regulation
  • Group III Histone Deacetylases
  • Plasmodium falciparum

abstract

  • Plasmodium falciparum, the most important causative agent of human malaria, undergoes antigenic variation as a means of prolonging infection and ensuring transmission between hosts. Clonal variation is observed in the surface adhesins expressed on infected erythrocytes: primarily in the PfEMP1 adhesin encoded by the large var gene family. The sirtuin PfSIR2A was the first protein discovered to have a major influence on antigenic variation in P. falciparum. In the absence of PfSIR2A, normal silencing of the variantly-expressed var gene family is partially deregulated. To thoroughly investigate the role of PfSIR2A in controlling antigenic variation, multiple independent clones of wildtype and PfSIR2A-knockout (DeltaSir2a) parasites were generated. var gene expression was then measured qualitatively, quantitatively and longitudinally over extended periods in culture. DeltaSir2a parasites were found to activate about 10 specific var genes in every independent clone analyzed. The activated genes were biased towards the upsA, upsBA and upsEvar gene subclasses. The total var transcript level was two to three-fold higher in DeltaSir2a parasites than in wildtype parasites and at least one transcript - encoding the pregnancy malaria adhesin VAR2CSA - was successfully translated and expressed on the infected cell surface. In the absence of PfSIR2A, antigenic switching over time was also diminished, although not abolished. This work expands our understanding of clonal antigenic variation in this important human pathogen and demonstrates a central role for PfSIR2A in regulating both the variant expression of specific var gene subsets and the overall quantity of var gene expression. Copyright 2009 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

publication date

  • January 2010

has subject area

  • Animals
  • Antigenic Variation
  • Cells, Cultured
  • Erythrocytes
  • Flow Cytometry
  • Gene Expression Regulation
  • Gene Silencing
  • Group III Histone Deacetylases
  • Histone Deacetylases
  • Humans
  • Malaria, Falciparum
  • Plasmodium falciparum
  • Reverse Transcriptase Polymerase Chain Reaction
  • Virulence

Research

keywords

  • Journal Article

Identity

Language

  • eng

Digital Object Identifier (DOI)

  • 10.1016/j.ijpara.2009.06.012

PubMed ID

  • 19666023

Additional Document Info

start page

  • 35

end page

  • 43

volume

  • 40

number

  • 1