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Team:USTC Software/Toggle-Switch
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The toggle switch is composed of two repressors and two promoters, each of which is inhibited by the repressor transcribed by the other promoter. We choose pLacI and pTetR as the two promoters, and the repressors are TetR and LacI, respectively. Theoretically, if ratio of LacI to TetR is greater than 1, strong binding of LacI to pLacI repress transcription initiation from pLacI and therefore quantities of TetR will decrease, which in turn relieves its repression to pTet leading to increase of quantities of LacI itself. In this situation, concentration of LacI is far greater than that of tetR, whose expression is repressed at an extream low level and the system enters into its 'LacI' state. Similar analysis will do for TetR and the system will enter into 'TetR' state if its quantity dominates. To show transition between the two states, IPTG is added in 1s after the system enters into 'LacI' state completely. The assembling of parts are construcuted as follows: | The toggle switch is composed of two repressors and two promoters, each of which is inhibited by the repressor transcribed by the other promoter. We choose pLacI and pTetR as the two promoters, and the repressors are TetR and LacI, respectively. Theoretically, if ratio of LacI to TetR is greater than 1, strong binding of LacI to pLacI repress transcription initiation from pLacI and therefore quantities of TetR will decrease, which in turn relieves its repression to pTet leading to increase of quantities of LacI itself. In this situation, concentration of LacI is far greater than that of tetR, whose expression is repressed at an extream low level and the system enters into its 'LacI' state. Similar analysis will do for TetR and the system will enter into 'TetR' state if its quantity dominates. To show transition between the two states, IPTG is added in 1s after the system enters into 'LacI' state completely. The assembling of parts are construcuted as follows: | ||
| - | [[Image:USTCs Toggle assembly.PNG| | + | [[Image:USTCs Toggle assembly.PNG|900px|thumb|center|Parts assembling: the top assembling is the construction used in our software and the bottom one is the toggle switch design in [http://www.nature.com/nature/journal/v403/n6767/full/403339a0.html Construction of a genetic toggle switch in Escherichia coli]. ]] |
where we use two consecutive terminators to indicate a complete termination. Time course simulation was performed to generate the state transition: | where we use two consecutive terminators to indicate a complete termination. Time course simulation was performed to generate the state transition: | ||
| - | [[Image:USTCs State conversion1.png| | + | [[Image:USTCs State conversion1.png|500px|thumb|center|State of system has changed to 'TetR' state from 'LacI' state after adding inducer IPTG at 40000s.]] |
The legend used in the figure is not so clearly. 13:DNA;(lacI153)4, 11:DNA;(tetR154)2, and 14:DNA;(lacI153)4;(tetR154)2 means binding products of initial plasmid with lacI tetramer at site pLacI gene, with tetR dimer at site pTet gene, and with lacI tetramer and tetR dimer both, respectively. | The legend used in the figure is not so clearly. 13:DNA;(lacI153)4, 11:DNA;(tetR154)2, and 14:DNA;(lacI153)4;(tetR154)2 means binding products of initial plasmid with lacI tetramer at site pLacI gene, with tetR dimer at site pTet gene, and with lacI tetramer and tetR dimer both, respectively. | ||
Revision as of 21:28, 26 October 2010
Toggle Switch
The toggle switch is composed of two repressors and two promoters, each of which is inhibited by the repressor transcribed by the other promoter. We choose pLacI and pTetR as the two promoters, and the repressors are TetR and LacI, respectively. Theoretically, if ratio of LacI to TetR is greater than 1, strong binding of LacI to pLacI repress transcription initiation from pLacI and therefore quantities of TetR will decrease, which in turn relieves its repression to pTet leading to increase of quantities of LacI itself. In this situation, concentration of LacI is far greater than that of tetR, whose expression is repressed at an extream low level and the system enters into its 'LacI' state. Similar analysis will do for TetR and the system will enter into 'TetR' state if its quantity dominates. To show transition between the two states, IPTG is added in 1s after the system enters into 'LacI' state completely. The assembling of parts are construcuted as follows:
where we use two consecutive terminators to indicate a complete termination. Time course simulation was performed to generate the state transition:
The legend used in the figure is not so clearly. 13:DNA;(lacI153)4, 11:DNA;(tetR154)2, and 14:DNA;(lacI153)4;(tetR154)2 means binding products of initial plasmid with lacI tetramer at site pLacI gene, with tetR dimer at site pTet gene, and with lacI tetramer and tetR dimer both, respectively.
