Dataset Information

Tagging of endogenous genes in a Toxoplasma gondii strain lacking Ku80.

ABSTRACT: As with other organisms with a completed genome sequence, opportunities for performing large-scale studies, such as expression and localization, on Toxoplasma gondii are now much more feasible. We present a system for tagging genes endogenously with yellow fluorescent protein (YFP) in a Deltaku80 strain. Ku80 is involved in DNA strand repair and nonhomologous DNA end joining; previous studies in other organisms have shown that in its absence, random integration is eliminated, allowing the insertion of constructs with homologous sequences into the proper loci. We generated a vector consisting of YFP and a dihydrofolate reductase-thymidylate synthase selectable marker. The YFP is preceded by a ligation-independent cloning (LIC) cassette, which allows the insertion of PCR products containing complementary LIC sequences. We demonstrated that the Deltaku80 strain is more effective and efficient in integrating the YFP-tagged constructs into the correct locus than wild-type strain RH. We then selected several hypothetical proteins that were identified by a proteomic screen of excreted-secreted antigens and that displayed microarray expression profiles similar to known micronemal proteins, with the thought that these could potentially be new proteins with roles in cell invasion. We localized these hypothetical proteins by YFP fluorescence and showed expression by immunoblotting. Our findings demonstrate that the combination of the Deltaku80 strain and the pYFP.LIC constructs reduces both the time and cost required to determine localization of a new gene of interest. This should allow the opportunity for performing larger-scale studies of novel T. gondii genes.

SUBMITTER: Huynh MH

PROVIDER: S-EPMC2669203 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature

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Tagging of endogenous genes in a Toxoplasma gondii strain lacking Ku80.

Huynh My-Hang MH Carruthers Vern B VB

Eukaryotic cell 20090213 4

As with other organisms with a completed genome sequence, opportunities for performing large-scale studies, such as expression and localization, on Toxoplasma gondii are now much more feasible. We present a system for tagging genes endogenously with yellow fluorescent protein (YFP) in a Deltaku80 strain. Ku80 is involved in DNA strand repair and nonhomologous DNA end joining; previous studies in other organisms have shown that in its absence, random integration is eliminated, allowing the insert ...[more]

PMID: 19218426

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Project description:Toxoplasma gondii is a globally distributed obligate intracellular parasite which can cause zoonotic toxoplasmosis with great harms. The average death time of mice that infected with Toxoplasma gondii RH strain tachyzoites recovered from the liquid nitrogen was shortened after multiple generations. It has been reported that the parasite is in a state of static virulence during cryopreservation and the virulence of the protozoan parasite can be enhanced after continuous passages in hosts under laboratory conditions. However, no research has been conducted to elucidate its biological mechanism. Herein, we sequenced the T. gondii transcriptome using RNA-Seq technology and performed de novo assembly to investigated the virulence factors expression changes by comparing gene expression profiles between incipiently recovered and completely resuscitated tachyzoites. Transcriptome analysis identified 1,951 differentially expressed transcripts in infected liver, of which 1,752 were significantly downregulated and 199 upregulated. We identified many differentially expressed proteins and genes, including serine/threonine kinase, calnexin, myosin and microtubule-associated protein which have previously been reported to be either involved in cell adhesion, parasite gliding or participate in cell invasion. The great majority of the virulence factors including microneme proteins, rhoptry proteins and dense granule proteins were upregulated in fully recovered tachyzoites. The enhanced virulence of recovered Toxoplasma gondii RH strain from the liquid nitrogen is associated with the up-regulated expression of MICs, ROPs and GRAs. Our data will facilitate future genomic research and in-depth annotation of Toxoplasma gondii RH strain genomes. This study provides a profile of the candidate genes that are suspected to be involved with virulence enhancement of recovered Toxoplasma gondii RH strain tachyzoites. Many further studies should be carried out to confirm the function of the candidate genes. Moreover, the preliminary identification of genes and pathways exhibiting differential expression in complete resuscitation stage may further our general understanding of virulence enhancement in this parasite.

Dataset Information

Tagging of endogenous genes in a Toxoplasma gondii strain lacking Ku80.

Publications

Tagging of endogenous genes in a Toxoplasma gondii strain lacking Ku80.

Similar Datasets

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