Comparative Proteomic Analysis of <i>Toxoplasma gondii</i> RH Wild-Type and Four SRS29B (SAG1) Knock-Out Clones Reveals Significant Differences between Individual Strains
In <i>T. gondii</i>, as well as in other model organisms, gene knock-out using CRISPR-Cas9 is a suitable tool to identify the role of specific genes. The general consensus implies that only the gene of interest is affected by the knock-out. Is this really the case? In a previous study, w...
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MDPI AG
2023-06-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/24/13/10454 |
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| author | Kai Pascal Alexander Hänggeli Andrew Hemphill Norbert Müller Manfred Heller Anne-Christine Uldry Sophie Braga-Lagache Joachim Müller Ghalia Boubaker |
| author_facet | Kai Pascal Alexander Hänggeli Andrew Hemphill Norbert Müller Manfred Heller Anne-Christine Uldry Sophie Braga-Lagache Joachim Müller Ghalia Boubaker |
| author_sort | Kai Pascal Alexander Hänggeli |
| collection | DOAJ |
| description | In <i>T. gondii</i>, as well as in other model organisms, gene knock-out using CRISPR-Cas9 is a suitable tool to identify the role of specific genes. The general consensus implies that only the gene of interest is affected by the knock-out. Is this really the case? In a previous study, we generated knock-out (KO) clones of TgRH88_077450 (SRS29B; SAG1) which differed in the numbers of the integrated dihydrofolate-reductase-thymidylate-synthase (MDHFR-TS) drug-selectable marker. Clones 18 and 33 had a single insertion of MDHFR-TS within SRS29B. Clone 6 was disrupted by the insertion of a short unrelated DNA-sequence, but the marker was integrated elsewhere. In clone 30, the marker was inserted into SRS29B, and several other MDHFR-TS copies were found in the genome. KO and wild-type (WT) tachyzoites had similar shapes, dimensions, and vitality. This prompted us to investigate the impact of genetic engineering on the overall proteome patterns of the four clones as compared to the respective WT. Comparative shotgun proteomics of the five strains was performed. Overall, 3236 proteins were identified. Principal component analysis of the proteomes revealed five distinct clusters corresponding to the five strains by both iTop3 and iLFQ algorithms. Detailed analysis of the differentially expressed proteins revealed that the target of the KO, srs29B, was lacking in all KO clones. In addition to this protein, 20 other proteins were differentially expressed between KO clones and WT or between different KO clones. The protein exhibiting the highest variation between the five strains was srs36D encoded by TgRH_016110. The deregulated expression of SRS36D was further validated by quantitative PCR. Moreover, the transcript levels of three other selected SRS genes, namely SRS36B, SRS46, and SRS57, exhibited significant differences between individual strains. These results indicate that knocking out a given gene may affect the expression of other genes. Therefore, care must be taken when specific phenotypes are regarded as a direct consequence of the KO of a given gene. |
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| issn | 1661-6596 1422-0067 |
| language | English |
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| spelling | doaj.art-ba16f7ca331549b4b4fc3de477bc1ccb2023-11-18T16:38:26ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672023-06-0124131045410.3390/ijms241310454Comparative Proteomic Analysis of <i>Toxoplasma gondii</i> RH Wild-Type and Four SRS29B (SAG1) Knock-Out Clones Reveals Significant Differences between Individual StrainsKai Pascal Alexander Hänggeli0Andrew Hemphill1Norbert Müller2Manfred Heller3Anne-Christine Uldry4Sophie Braga-Lagache5Joachim Müller6Ghalia Boubaker7Department of Infectious Diseases and Pathobiology, Institute of Parasitology, University of Bern, 3012 Bern, SwitzerlandDepartment of Infectious Diseases and Pathobiology, Institute of Parasitology, University of Bern, 3012 Bern, SwitzerlandDepartment of Infectious Diseases and Pathobiology, Institute of Parasitology, University of Bern, 3012 Bern, SwitzerlandProteomics and Mass Spectrometry Core Facility (PMSCF), Department for BioMedical Research (DBMR), University of Bern, 3012 Bern, SwitzerlandProteomics and Mass Spectrometry Core Facility (PMSCF), Department for BioMedical Research (DBMR), University of Bern, 3012 Bern, SwitzerlandProteomics and Mass Spectrometry Core Facility (PMSCF), Department for BioMedical Research (DBMR), University of Bern, 3012 Bern, SwitzerlandDepartment of Infectious Diseases and Pathobiology, Institute of Parasitology, University of Bern, 3012 Bern, SwitzerlandDepartment of Infectious Diseases and Pathobiology, Institute of Parasitology, University of Bern, 3012 Bern, SwitzerlandIn <i>T. gondii</i>, as well as in other model organisms, gene knock-out using CRISPR-Cas9 is a suitable tool to identify the role of specific genes. The general consensus implies that only the gene of interest is affected by the knock-out. Is this really the case? In a previous study, we generated knock-out (KO) clones of TgRH88_077450 (SRS29B; SAG1) which differed in the numbers of the integrated dihydrofolate-reductase-thymidylate-synthase (MDHFR-TS) drug-selectable marker. Clones 18 and 33 had a single insertion of MDHFR-TS within SRS29B. Clone 6 was disrupted by the insertion of a short unrelated DNA-sequence, but the marker was integrated elsewhere. In clone 30, the marker was inserted into SRS29B, and several other MDHFR-TS copies were found in the genome. KO and wild-type (WT) tachyzoites had similar shapes, dimensions, and vitality. This prompted us to investigate the impact of genetic engineering on the overall proteome patterns of the four clones as compared to the respective WT. Comparative shotgun proteomics of the five strains was performed. Overall, 3236 proteins were identified. Principal component analysis of the proteomes revealed five distinct clusters corresponding to the five strains by both iTop3 and iLFQ algorithms. Detailed analysis of the differentially expressed proteins revealed that the target of the KO, srs29B, was lacking in all KO clones. In addition to this protein, 20 other proteins were differentially expressed between KO clones and WT or between different KO clones. The protein exhibiting the highest variation between the five strains was srs36D encoded by TgRH_016110. The deregulated expression of SRS36D was further validated by quantitative PCR. Moreover, the transcript levels of three other selected SRS genes, namely SRS36B, SRS46, and SRS57, exhibited significant differences between individual strains. These results indicate that knocking out a given gene may affect the expression of other genes. Therefore, care must be taken when specific phenotypes are regarded as a direct consequence of the KO of a given gene.https://www.mdpi.com/1422-0067/24/13/10454genetic manipulationpleiotropic effectssystems biology |
| spellingShingle | Kai Pascal Alexander Hänggeli Andrew Hemphill Norbert Müller Manfred Heller Anne-Christine Uldry Sophie Braga-Lagache Joachim Müller Ghalia Boubaker Comparative Proteomic Analysis of <i>Toxoplasma gondii</i> RH Wild-Type and Four SRS29B (SAG1) Knock-Out Clones Reveals Significant Differences between Individual Strains International Journal of Molecular Sciences genetic manipulation pleiotropic effects systems biology |
| title | Comparative Proteomic Analysis of <i>Toxoplasma gondii</i> RH Wild-Type and Four SRS29B (SAG1) Knock-Out Clones Reveals Significant Differences between Individual Strains |
| title_full | Comparative Proteomic Analysis of <i>Toxoplasma gondii</i> RH Wild-Type and Four SRS29B (SAG1) Knock-Out Clones Reveals Significant Differences between Individual Strains |
| title_fullStr | Comparative Proteomic Analysis of <i>Toxoplasma gondii</i> RH Wild-Type and Four SRS29B (SAG1) Knock-Out Clones Reveals Significant Differences between Individual Strains |
| title_full_unstemmed | Comparative Proteomic Analysis of <i>Toxoplasma gondii</i> RH Wild-Type and Four SRS29B (SAG1) Knock-Out Clones Reveals Significant Differences between Individual Strains |
| title_short | Comparative Proteomic Analysis of <i>Toxoplasma gondii</i> RH Wild-Type and Four SRS29B (SAG1) Knock-Out Clones Reveals Significant Differences between Individual Strains |
| title_sort | comparative proteomic analysis of i toxoplasma gondii i rh wild type and four srs29b sag1 knock out clones reveals significant differences between individual strains |
| topic | genetic manipulation pleiotropic effects systems biology |
| url | https://www.mdpi.com/1422-0067/24/13/10454 |
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