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Team:Uppsala/toxin-antitoxin-system
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| - | <h1 class="main-title"> Toxin-antitoxin system </h1> | + | <h1 class="main-title-left"> Toxin-antitoxin system </h1> |
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| - | < | + | <h1> Keep your plasmids without antibiotic resistance </h1> |
One of the challenges when creating synthetic systems in bacteria that serve a purpose besides increasing the fitness of the organism is that there is a negative selective pressure against keeping the system. Toxin-antitoxin systems can be used to make plasmids far more stabile without having to use antibiotics and antibiotic resistance. If a clone were to lose the plasmid, the toxin which usually has a longer half life than the antitoxin will kill the bacteria. | One of the challenges when creating synthetic systems in bacteria that serve a purpose besides increasing the fitness of the organism is that there is a negative selective pressure against keeping the system. Toxin-antitoxin systems can be used to make plasmids far more stabile without having to use antibiotics and antibiotic resistance. If a clone were to lose the plasmid, the toxin which usually has a longer half life than the antitoxin will kill the bacteria. | ||
| - | < | + | <img class="method-plasmid" src="https://static.igem.org/mediawiki/2013/d/dc/Uppsala2013_anti-toxin-toxin-system.jpg"> |
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| + | <p>Above is an example of how a toxin-antitoxin system could be applied together with a gene X. If the gene is toxic or expressed strongly enough there will be a substantial evolutionary pressure to lose the plasmid during cell division. However if the gene is present on a plasmid with a toxin-antitoxin system would be lethal due to the loss of the antitoxin gene.</p> | ||
| - | < | + | <h1> A natural toxin-antitoxin from lactobacillus plantarum </h1> |
We have taken the Pem toxin-antitoxin system from plasmid p256 that was originally isolated from lactobacillus plantarum NC7. The system consists of a single operon and consists of two ORFs, one for the toxin and antitoxin respectively. Pem on p256 has been shown to increase segregational stability under non-selective pressure. The system has experimentally been shown to allow 88-100% retention of a plasmid after 80 generations(1). We have provided the toxin-antitoxin system both with and without a natural putative promoter. | We have taken the Pem toxin-antitoxin system from plasmid p256 that was originally isolated from lactobacillus plantarum NC7. The system consists of a single operon and consists of two ORFs, one for the toxin and antitoxin respectively. Pem on p256 has been shown to increase segregational stability under non-selective pressure. The system has experimentally been shown to allow 88-100% retention of a plasmid after 80 generations(1). We have provided the toxin-antitoxin system both with and without a natural putative promoter. | ||
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| - | < | + | <h1> References: </h1> |
http://mic.sgmjournals.org/content/151/2/421.long (1) | http://mic.sgmjournals.org/content/151/2/421.long (1) | ||
Revision as of 05:51, 29 September 2013
Toxin-antitoxin system
Keep your plasmids without antibiotic resistance
One of the challenges when creating synthetic systems in bacteria that serve a purpose besides increasing the fitness of the organism is that there is a negative selective pressure against keeping the system. Toxin-antitoxin systems can be used to make plasmids far more stabile without having to use antibiotics and antibiotic resistance. If a clone were to lose the plasmid, the toxin which usually has a longer half life than the antitoxin will kill the bacteria.
Above is an example of how a toxin-antitoxin system could be applied together with a gene X. If the gene is toxic or expressed strongly enough there will be a substantial evolutionary pressure to lose the plasmid during cell division. However if the gene is present on a plasmid with a toxin-antitoxin system would be lethal due to the loss of the antitoxin gene.
A natural toxin-antitoxin from lactobacillus plantarum
We have taken the Pem toxin-antitoxin system from plasmid p256 that was originally isolated from lactobacillus plantarum NC7. The system consists of a single operon and consists of two ORFs, one for the toxin and antitoxin respectively. Pem on p256 has been shown to increase segregational stability under non-selective pressure. The system has experimentally been shown to allow 88-100% retention of a plasmid after 80 generations(1). We have provided the toxin-antitoxin system both with and without a natural putative promoter.References:
http://mic.sgmjournals.org/content/151/2/421.long (1)
