The BSR4 protein is up-regulated in Toxoplasma gondii bradyzoites, however the dominant surface antigen recognised by the P36 monoclonal antibody is SRS9

Van, Tam T.; Kim, Seon-Kyeong; Camps, Manel; Boothroyd, John C.; Knoll, Laura J.

doi:10.1016/j.ijpara.2007.02.001

Cited by 24 publications

(23 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…3A ; all primers used for promoter constructs in these and all experiments below are listed in Table S2 ). Note that the BSR4 (641.m01561) promoter construct was constitutively expressed in these assays, which is consistent with the SAGE frequencies obtained for this gene and the revised assignment of this mRNA as being translationally controlled ( Knoll and Boothroyd, 1998 ; Van et al ., 2007 ). A number of other promoters tested had moderate to high levels of expression in tachyzoites ( Fig.…”

Section: Resultssupporting

confidence: 85%

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

Behnke

Radke

Smith

et al. 2008

Molecular Microbiology

137

View full text Add to dashboard Cite

SummaryExperimental 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 ciselements 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.

show abstract

Section: Resultssupporting

confidence: 85%

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

Behnke

Radke

Smith

et al. 2008

Molecular Microbiology

137

View full text Add to dashboard Cite

show abstract

“…6B). a. TGME49_120190 (SRS9) is a known bradyzoite marker (Van et al, 2007), despite the lack of strong upregulation in pH 8.2-stressed wild-type parasites in this experiment.…”

Section: Bradyzoite Markers and Cyst Burden Are Reduced In The Type Imentioning

confidence: 66%

The Toxoplasma nuclear factor TgAP2XI‐4 controls bradyzoite gene expression and cyst formation

Walker

Gissot

Croken

et al. 2012

Molecular Microbiology

View full text Add to dashboard Cite

Toxoplasma gondii undergoes many phenotypic changes during its life cycle. The recent identification of AP2 transcription factors in T. gondii has provided a platform for studying the mechanisms controlling gene expression. In the present study, we report that a recombinant protein encompassing the TgAP2XI-4 AP2 domain was able to specifically bind to a DNA motif using gel retardation assays. TgAP2XI-4 protein is localised in the parasite nucleus throughout the tachyzoite life-cycle in vitro, with peak expression occurring after cytokinesis. We found that the TgAP2XI-4 transcript level was higher in bradyzoite cysts isolated from brains of chronically infected mice than in the rapidly replicating tachyzoites. A knock-out of the TgAP2XI-4 gene in both T. gondii virulent type I and avirulent type II strains reveals its role in modulating expression and promoter activity of genes involved in stage conversion of the rapidly replicating tachyzoites to the dormant cyst forming bradyzoites. Furthermore, mice infected with the type II KO mutants show a drastically reduced brain cyst burden. Thus, our results validate TgAP2XI-4 as a novel nuclear factor that regulates bradyzoite gene expression during parasite differentiation and cyst formation.

show abstract

“…By IFA, SUSA1-GFP driven by the native promoter was expressed robustly and colocalized with SRS9, a bradyzoite-specific SAG1 family surface antigen that is the main interactive protein with the P36 monoclonal antibody (Fig. 5B) (28). These results show that the expression of at least one member of this new family of surface antigens is controlled during infection.…”

Section: Resultsmentioning

confidence: 71%

Highly Polymorphic Family of Glycosylphosphatidylinositol-Anchored Surface Antigens with Evidence of Developmental Regulation in Toxoplasma gondii

et al. 2008

Self Cite

View full text Add to dashboard Cite

The life cycle of the apicomplexan parasite Toxoplasma gondii requires that an infectious cyst develop and be maintained throughout the life of the host. The molecules displayed on the parasite surface are important in controlling the immune response to the parasite. T. gondii has a superfamily of glycosylphosphatidylinositol (GPI)-anchored surface antigens, termed the surface antigen (SAG) and SAG-related surface antigens, that are developmentally regulated during infection. Using a clustering algorithm, we identified a new family of 31 surface proteins that are predicted to be GPI anchored but are unrelated to the SAG proteins, and thus we named these proteins SAG-unrelated surface antigens (SUSA). Analysis of the single nucleotide polymorphism density showed that the members of this family are the most polymorphic genes within the T. gondii genome. Immunofluorescence of SUSA1 and SUSA2, two members of the family, revealed that they are found on the parasite surface. We confirmed that SUSA1 and SUSA2 are GPI anchored by phospholipase cleavage. Analysis of expressed sequence tags (ESTs) revealed that SUSA1 had 22 of 23 ESTs from chronic infection. Analysis of mRNA and protein confirmed that SUSA1 is highly expressed in the chronic form of the parasite. Sera from mice with chronic T. gondii infection reacted to SUSA1, indicating that SUSA1 interacts with the host immune system during infection. This group of proteins likely represents a new family of polymorphic GPI-anchored surface antigens that are recognized by the host's immune system and whose expression is regulated during infection.Toxoplasma gondii is an obligate intracellular parasite and a member of the phylum Apicomplexa, which also includes Plasmodium, Cryptosporidium, Cyclospora, Eimeria, and Sarcocystis (3). T. gondii can reproduce both sexually and asexually. Sexual reproduction occurs only in the feline intestine and results in oocysts being shed in the feces. Within the environment, oocysts develop into infectious sporozoites. The asexual cycle has two developmental stages, namely, a rapidly replicating form called the tachyzoite and a slow-growing stage called the bradyzoite. Bradyzoites form tissue cysts in the central nervous system and muscle tissue and represent the chronic stage of infection. T. gondii is acquired orally either by ingestion of oocyst-contaminated foods or by eating undercooked, bradyzoite-harboring meat products. T. gondii infections in immunocompetent individuals are generally asymptomatic, but infections in immunocompromised individuals and fetuses are life-threatening (9).Despite its ability to reproduce sexually and its broad geographic range, T. gondii has a largely clonal population structure comprised principally of three lines (15,25). Analysis of genetic polymorphisms indicates that these three lines emerged from a single genetic cross approximately 10,000 years ago (27), establishing two major alleles for each locus (12). The type I lineage is highly virulent, with injection of one viable parasite being lethal to...

show abstract

The BSR4 protein is up-regulated in Toxoplasma gondii bradyzoites, however the dominant surface antigen recognised by the P36 monoclonal antibody is SRS9

Cited by 24 publications

References 26 publications

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

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

The Toxoplasma nuclear factor TgAP2XI‐4 controls bradyzoite gene expression and cyst formation

Highly Polymorphic Family of Glycosylphosphatidylinositol-Anchored Surface Antigens with Evidence of Developmental Regulation in Toxoplasma gondii

Contact Info

Product

Resources

About