{"id":{"repo_id":"dundee","oai_identifier":"oai:discovery.dundee.ac.uk:studenttheses/4ac77951-a5bd-4913-9205-8faed5d7ff0e"},"canonical_url":"https://search.dev.ndltd.org/etd/dundee/oai:discovery.dundee.ac.uk:studenttheses/4ac77951-a5bd-4913-9205-8faed5d7ff0e","repository":{"repo_id":"dundee","name":"University of Dundee","base_url":"https://discovery.dundee.ac.uk/ws/oai"},"display":{"title":"Investigating the role of TspA, a novel substrate of the <i>Staphylococcus aureus</i> Type VII protein secretion system","abstract":"The Gram-positive bacterium <i>Staphylococcus aureus</i> is a major pathogen of humans and one of the leading causes of community- and hospital-acquired infections. The Type VII Secretion System (T7SS) is widespread in Gram-positive bacteria belonging to both the Actinobacteria and Firmicutes phyla. In commonly-studied strains of <i>S. aureus</i> the T7SS gene cluster is encoded by 12 genes, and it has been shown to play an important role in virulence and interbacterial competition. To date, very few T7SS-dependent substrates of known biological function have been identified. In this study an unbiased mass-spectrometry approach was used to identify candidate T7 substrate proteins. A previously uncharacterised protein, SAOUHSC_00584, was found in the culture supernatant in a T7-dependent manner. Cell fractionation and protease accessibility experiments demonstrated that SAOUHSC_00584 is a peripheral membrane protein that localises at the extracellular side of the membrane. The stability of SAOUHSC_00584 was shown to be dependent on the EssC componentof the T7SS. Structural modelling suggested that SAOUHSC_00584 shares homology to the pore-forming protein colicin Ia. The C-terminal domain of SAOUHSC_00584 was shown to have toxic activity when produced in the periplasm of <i>Escherichia coli</i>, and that it depolarised the cytoplasmic membrane. It was subsequently re-named TspA. TspA is encoded at a genetic locus with multiple DUF443 domain-encoding proteins. The neighbouring gene, <i>SAOUHSC_00585</i> (<i>tsaI</i>) was shown to encode a membrane protein that confers immunity to the toxic activity of TspA. A zebrafish larva hindbrain infection model was developed to investigate biological roles of the T7SS and TspA. Using this model it was seen that there was a role for the T7SS and for TspA in <i>S. aureus</i> virulence. The model was also adapted to assess interbacterial competition <i>in vivo</i>. TspA was shown to contribute to intra-species growth inhibition. Thus TspA is a T7-secreted toxin with the unusual property of targeting both eukaryotes and prokaryotes.<br/>","abstract_html":"The Gram-positive bacterium &lt;i&gt;Staphylococcus aureus&lt;/i&gt; is a major pathogen of humans and one of the leading causes of community- and hospital-acquired infections. The Type VII Secretion System (T7SS) is widespread in Gram-positive bacteria belonging to both the Actinobacteria and Firmicutes phyla. In commonly-studied strains of &lt;i&gt;S. aureus&lt;/i&gt; the T7SS gene cluster is encoded by 12 genes, and it has been shown to play an important role in virulence and interbacterial competition. To date, very few T7SS-dependent substrates of known biological function have been identified. In this study an unbiased mass-spectrometry approach was used to identify candidate T7 substrate proteins. A previously uncharacterised protein, SAOUHSC_00584, was found in the culture supernatant in a T7-dependent manner. Cell fractionation and protease accessibility experiments demonstrated that SAOUHSC_00584 is a peripheral membrane protein that localises at the extracellular side of the membrane. The stability of SAOUHSC_00584 was shown to be dependent on the EssC componentof the T7SS. Structural modelling suggested that SAOUHSC_00584 shares homology to the pore-forming protein colicin Ia. The C-terminal domain of SAOUHSC_00584 was shown to have toxic activity when produced in the periplasm of &lt;i&gt;Escherichia coli&lt;/i&gt;, and that it depolarised the cytoplasmic membrane. It was subsequently re-named TspA. TspA is encoded at a genetic locus with multiple DUF443 domain-encoding proteins. The neighbouring gene, &lt;i&gt;SAOUHSC_00585&lt;/i&gt; (&lt;i&gt;tsaI&lt;/i&gt;) was shown to encode a membrane protein that confers immunity to the toxic activity of TspA. A zebrafish larva hindbrain infection model was developed to investigate biological roles of the T7SS and TspA. Using this model it was seen that there was a role for the T7SS and for TspA in &lt;i&gt;S. aureus&lt;/i&gt; virulence. The model was also adapted to assess interbacterial competition &lt;i&gt;in vivo&lt;/i&gt;. TspA was shown to contribute to intra-species growth inhibition. Thus TspA is a T7-secreted toxin with the unusual property of targeting both eukaryotes and prokaryotes.&lt;br/&gt;","abstract_has_math":false,"creators":["Ulhuq, Fatima"],"institution":"University of Dundee","degree_name":"Doctor of Philosophy","degree_level":"Doctoral Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Palmer, Tracy"],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020","date_published":"2020","updated_at":"2026-07-24T02:08:52Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["oai:discovery.dundee.ac.uk:studenttheses/4ac77951-a5bd-4913-9205-8faed5d7ff0e"],"render_values":[{"text":"oai:discovery.dundee.ac.uk:studenttheses/4ac77951-a5bd-4913-9205-8faed5d7ff0e","href":null,"code":true}]}]},"links":{"outbound_url":"https://discovery.dundee.ac.uk/en/studentTheses/4ac77951-a5bd-4913-9205-8faed5d7ff0e","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Palmer, Tracy"]},{"key":"dc:contributor.sponsor","label":"Sponsor","values":["Biotechnology and Biological Sciences Research Council","BBSRC EASTBIO DTP Studentship"]},{"key":"dc:creator","label":"Author","values":["Ulhuq, Fatima"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2020"]},{"key":"dc:date.issued","label":"Date","values":["2020"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["DArcy Thompson Unit","Molecular Microbiology"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Dundee"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://discovery.dundee.ac.uk/en/studentTheses/4ac77951-a5bd-4913-9205-8faed5d7ff0e"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral Thesis"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Doctor of Philosophy"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights.embargodate","label":"Dc Rights Embargodate","values":["2022-06-30"]},{"key":"dc:rights.embargoreason","label":"Dc Rights Embargoreason","values":["/dk/atira/pure/core/document/studentthesisembargoreason/commercialexploitation"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["oai:discovery.dundee.ac.uk:studenttheses/4ac77951-a5bd-4913-9205-8faed5d7ff0e","https://discovery.dundee.ac.uk/en/studentTheses/4ac77951-a5bd-4913-9205-8faed5d7ff0e"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://discovery.dundee.ac.uk/files/42194606/Ulhuq_Fatima_Thesis_2020.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The Gram-positive bacterium <i>Staphylococcus aureus</i> is a major pathogen of humans and one of the leading causes of community- and hospital-acquired infections. The Type VII Secretion System (T7SS) is widespread in Gram-positive bacteria belonging to both the Actinobacteria and Firmicutes phyla. In commonly-studied strains of <i>S. aureus</i> the T7SS gene cluster is encoded by 12 genes, and it has been shown to play an important role in virulence and interbacterial competition. To date, very few T7SS-dependent substrates of known biological function have been identified. In this study an unbiased mass-spectrometry approach was used to identify candidate T7 substrate proteins. A previously uncharacterised protein, SAOUHSC_00584, was found in the culture supernatant in a T7-dependent manner. Cell fractionation and protease accessibility experiments demonstrated that SAOUHSC_00584 is a peripheral membrane protein that localises at the extracellular side of the membrane. The stability of SAOUHSC_00584 was shown to be dependent on the EssC componentof the T7SS. Structural modelling suggested that SAOUHSC_00584 shares homology to the pore-forming protein colicin Ia. The C-terminal domain of SAOUHSC_00584 was shown to have toxic activity when produced in the periplasm of <i>Escherichia coli</i>, and that it depolarised the cytoplasmic membrane. It was subsequently re-named TspA. TspA is encoded at a genetic locus with multiple DUF443 domain-encoding proteins. The neighbouring gene, <i>SAOUHSC_00585</i> (<i>tsaI</i>) was shown to encode a membrane protein that confers immunity to the toxic activity of TspA. A zebrafish larva hindbrain infection model was developed to investigate biological roles of the T7SS and TspA. Using this model it was seen that there was a role for the T7SS and for TspA in <i>S. aureus</i> virulence. The model was also adapted to assess interbacterial competition <i>in vivo</i>. TspA was shown to contribute to intra-species growth inhibition. Thus TspA is a T7-secreted toxin with the unusual property of targeting both eukaryotes and prokaryotes.<br/>"]},{"key":"dc:title","label":"Title","values":["Investigating the role of TspA, a novel substrate of the <i>Staphylococcus aureus</i> Type VII protein secretion system"]}]}],"canonical_facts":{"dc:contributor.advisor":["Palmer, Tracy"],"dc:contributor.sponsor":["Biotechnology and Biological Sciences Research Council","BBSRC EASTBIO DTP Studentship"],"dc:creator":["Ulhuq, Fatima"],"dc:date":["2020"],"dc:date.issued":["2020"],"dc:description.abstract":["The Gram-positive bacterium <i>Staphylococcus aureus</i> is a major pathogen of humans and one of the leading causes of community- and hospital-acquired infections. The Type VII Secretion System (T7SS) is widespread in Gram-positive bacteria belonging to both the Actinobacteria and Firmicutes phyla. In commonly-studied strains of <i>S. aureus</i> the T7SS gene cluster is encoded by 12 genes, and it has been shown to play an important role in virulence and interbacterial competition. To date, very few T7SS-dependent substrates of known biological function have been identified. In this study an unbiased mass-spectrometry approach was used to identify candidate T7 substrate proteins. A previously uncharacterised protein, SAOUHSC_00584, was found in the culture supernatant in a T7-dependent manner. Cell fractionation and protease accessibility experiments demonstrated that SAOUHSC_00584 is a peripheral membrane protein that localises at the extracellular side of the membrane. The stability of SAOUHSC_00584 was shown to be dependent on the EssC componentof the T7SS. Structural modelling suggested that SAOUHSC_00584 shares homology to the pore-forming protein colicin Ia. The C-terminal domain of SAOUHSC_00584 was shown to have toxic activity when produced in the periplasm of <i>Escherichia coli</i>, and that it depolarised the cytoplasmic membrane. It was subsequently re-named TspA. TspA is encoded at a genetic locus with multiple DUF443 domain-encoding proteins. The neighbouring gene, <i>SAOUHSC_00585</i> (<i>tsaI</i>) was shown to encode a membrane protein that confers immunity to the toxic activity of TspA. A zebrafish larva hindbrain infection model was developed to investigate biological roles of the T7SS and TspA. Using this model it was seen that there was a role for the T7SS and for TspA in <i>S. aureus</i> virulence. The model was also adapted to assess interbacterial competition <i>in vivo</i>. TspA was shown to contribute to intra-species growth inhibition. Thus TspA is a T7-secreted toxin with the unusual property of targeting both eukaryotes and prokaryotes.<br/>"],"dc:identifier":["oai:discovery.dundee.ac.uk:studenttheses/4ac77951-a5bd-4913-9205-8faed5d7ff0e","https://discovery.dundee.ac.uk/en/studentTheses/4ac77951-a5bd-4913-9205-8faed5d7ff0e"],"dc:identifier.uri":["https://discovery.dundee.ac.uk/files/42194606/Ulhuq_Fatima_Thesis_2020.pdf"],"dc:language":["eng"],"dc:publisher.department":["DArcy Thompson Unit","Molecular Microbiology"],"dc:publisher.institution":["University of Dundee"],"dc:relation.isreferencedby":["https://discovery.dundee.ac.uk/en/studentTheses/4ac77951-a5bd-4913-9205-8faed5d7ff0e"],"dc:rights.embargodate":["2022-06-30"],"dc:rights.embargoreason":["/dk/atira/pure/core/document/studentthesisembargoreason/commercialexploitation"],"dc:title":["Investigating the role of TspA, a novel substrate of the <i>Staphylococcus aureus</i> Type VII protein secretion system"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["Doctoral Thesis"],"dc:type.qualificationname":["Doctor of Philosophy"]},"updated_at":"2026-07-24T02:08:52Z"}