The transcription of bradyzoite genes in Toxoplasma gondii is controlled by autonomous promoter elements

Michael S. Behnke, Josh B. Radke, Aaron T. Smith, William Sullivan, Michael W. White

Research output: Contribution to journalArticle

69 Citations (Scopus)

Abstract

Experimental evidence suggests that apicomplexan parasites possess bipartite promoters with basal and regulated cis-elements similar to other eukaryotes. Using a dual luciferase model adapted for recombinational cloning and use in Toxoplasma gondii, we show that genomic regions flanking 16 parasite genes, which encompass examples of constitutive and tachyzoite- and bradyzoite-specific genes, are able to reproduce the appropriate developmental stage expression in a transient luciferase assay. Mapping of cis-acting elements in several bradyzoite promoters led to the identification of short sequence spans that are involved in control of bradyzoite gene expression in multiple strains and under different bradyzoite induction conditions. Promoters that regulate the heat shock protein BAG1 and a novel bradyzoite-specific NTPase during bradyzoite development were fine mapped to a 6-8 bp resolution and these minimal cis-elements were capable of converting a constitutive promoter to one that is induced by bradyzoite conditions. Gel-shift experiments show that mapped cis-elements are bound by parasite protein factors with the appropriate functional sequence specificity. These studies are the first to identify the minimal sequence elements that are required and sufficient for bradyzoite gene expression and to show that bradyzoite promoters are maintained in a 'poised' chromatin state throughout the intermediate host life cycle in low passage strains. Together, these data demonstrate that conventional eukaryotic promoter mechanisms work with epigenetic processes to regulate developmental gene expression during tissue cyst formation.

Original languageEnglish
Pages (from-to)1502-1518
Number of pages17
JournalMolecular Microbiology
Volume68
Issue number6
DOIs
StatePublished - Jun 2008

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Toxoplasma
Parasites
Luciferases
Gene Expression
Nucleoside-Triphosphatase
Genetic Epigenesis
Genes
Developmental Genes
Heat-Shock Proteins
Life Cycle Stages
Eukaryota
Chromatin
Cysts
Organism Cloning
Gels
Proteins

ASJC Scopus subject areas

  • Molecular Biology
  • Microbiology

Cite this

The transcription of bradyzoite genes in Toxoplasma gondii is controlled by autonomous promoter elements. / Behnke, Michael S.; Radke, Josh B.; Smith, Aaron T.; Sullivan, William; White, Michael W.

In: Molecular Microbiology, Vol. 68, No. 6, 06.2008, p. 1502-1518.

Research output: Contribution to journalArticle

Behnke, Michael S. ; Radke, Josh B. ; Smith, Aaron T. ; Sullivan, William ; White, Michael W. / The transcription of bradyzoite genes in Toxoplasma gondii is controlled by autonomous promoter elements. In: Molecular Microbiology. 2008 ; Vol. 68, No. 6. pp. 1502-1518.
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