Insights into Transcriptional Repression of the Homologous Toxin-Antitoxin Cassettes <i>yefM-yoeB</i> and <i>axe-txe</i>
Transcriptional repression is a mechanism which enables effective gene expression switch off. The activity of most of type II toxin-antitoxin (TA) cassettes is controlled in this way. These cassettes undergo negative autoregulation by the TA protein complex which binds to the promoter/operator seque...
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MDPI AG
2020-11-01
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| Series: | International Journal of Molecular Sciences |
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| author | Barbara Kędzierska Katarzyna Potrykus Agnieszka Szalewska-Pałasz Beata Wodzikowska |
| author_facet | Barbara Kędzierska Katarzyna Potrykus Agnieszka Szalewska-Pałasz Beata Wodzikowska |
| author_sort | Barbara Kędzierska |
| collection | DOAJ |
| description | Transcriptional repression is a mechanism which enables effective gene expression switch off. The activity of most of type II toxin-antitoxin (TA) cassettes is controlled in this way. These cassettes undergo negative autoregulation by the TA protein complex which binds to the promoter/operator sequence and blocks transcription initiation of the TA operon. Precise and tight control of this process is vital to avoid uncontrolled expression of the toxin component. Here, we employed a series of in vivo and in vitro experiments to establish the molecular basis for previously observed differences in transcriptional activity and repression levels of the <i>p<sub>yy</sub></i> and <i>p<sub>at</sub></i> promoters which control expression of two homologous TA systems, YefM-YoeB and Axe-Txe, respectively. Transcriptional fusions of promoters with a <i>lux</i> reporter, together with in vitro transcription, EMSA and footprinting assays revealed that: (1) the different sequence composition of the −35 promoter element is responsible for substantial divergence in strengths of the promoters; (2) variations in repression result from the TA repressor complex acting at different steps in the transcription initiation process; (3) transcription from an additional promoter upstream of <i>p<sub>at</sub></i> also contributes to the observed inefficient repression of <i>axe-txe</i> module. This study provides evidence that even closely related TA cassettes with high sequence similarity in the promoter/operator region may employ diverse mechanisms for transcriptional regulation of their genes. |
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| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T14:28:24Z |
| publishDate | 2020-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-abcc25b8ce4f41f8a038ecb537dee73d2023-11-20T22:46:58ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672020-11-012123906210.3390/ijms21239062Insights into Transcriptional Repression of the Homologous Toxin-Antitoxin Cassettes <i>yefM-yoeB</i> and <i>axe-txe</i>Barbara Kędzierska0Katarzyna Potrykus1Agnieszka Szalewska-Pałasz2Beata Wodzikowska3Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, PolandDepartment of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, PolandDepartment of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, PolandDepartment of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, PolandTranscriptional repression is a mechanism which enables effective gene expression switch off. The activity of most of type II toxin-antitoxin (TA) cassettes is controlled in this way. These cassettes undergo negative autoregulation by the TA protein complex which binds to the promoter/operator sequence and blocks transcription initiation of the TA operon. Precise and tight control of this process is vital to avoid uncontrolled expression of the toxin component. Here, we employed a series of in vivo and in vitro experiments to establish the molecular basis for previously observed differences in transcriptional activity and repression levels of the <i>p<sub>yy</sub></i> and <i>p<sub>at</sub></i> promoters which control expression of two homologous TA systems, YefM-YoeB and Axe-Txe, respectively. Transcriptional fusions of promoters with a <i>lux</i> reporter, together with in vitro transcription, EMSA and footprinting assays revealed that: (1) the different sequence composition of the −35 promoter element is responsible for substantial divergence in strengths of the promoters; (2) variations in repression result from the TA repressor complex acting at different steps in the transcription initiation process; (3) transcription from an additional promoter upstream of <i>p<sub>at</sub></i> also contributes to the observed inefficient repression of <i>axe-txe</i> module. This study provides evidence that even closely related TA cassettes with high sequence similarity in the promoter/operator region may employ diverse mechanisms for transcriptional regulation of their genes.https://www.mdpi.com/1422-0067/21/23/9062transcription repressionhomologous toxin-antitoxinYefM-YoeBAxe-Txe |
| spellingShingle | Barbara Kędzierska Katarzyna Potrykus Agnieszka Szalewska-Pałasz Beata Wodzikowska Insights into Transcriptional Repression of the Homologous Toxin-Antitoxin Cassettes <i>yefM-yoeB</i> and <i>axe-txe</i> International Journal of Molecular Sciences transcription repression homologous toxin-antitoxin YefM-YoeB Axe-Txe |
| title | Insights into Transcriptional Repression of the Homologous Toxin-Antitoxin Cassettes <i>yefM-yoeB</i> and <i>axe-txe</i> |
| title_full | Insights into Transcriptional Repression of the Homologous Toxin-Antitoxin Cassettes <i>yefM-yoeB</i> and <i>axe-txe</i> |
| title_fullStr | Insights into Transcriptional Repression of the Homologous Toxin-Antitoxin Cassettes <i>yefM-yoeB</i> and <i>axe-txe</i> |
| title_full_unstemmed | Insights into Transcriptional Repression of the Homologous Toxin-Antitoxin Cassettes <i>yefM-yoeB</i> and <i>axe-txe</i> |
| title_short | Insights into Transcriptional Repression of the Homologous Toxin-Antitoxin Cassettes <i>yefM-yoeB</i> and <i>axe-txe</i> |
| title_sort | insights into transcriptional repression of the homologous toxin antitoxin cassettes i yefm yoeb i and i axe txe i |
| topic | transcription repression homologous toxin-antitoxin YefM-YoeB Axe-Txe |
| url | https://www.mdpi.com/1422-0067/21/23/9062 |
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