Team:Tokyo Tech/Genetic toggle switch to implement rewritable function

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== Mathematical model ==
== Mathematical model ==
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<gallery widths="300px" heights="200px" perrow="1" align="right" caption="Differential equation models">
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We used two differential equation models and we call them 'atmospheric pressure model' and '30MPa pressure model'.
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Image:Room_pressure_model.png|figure 5-2 Atmospheric pressure model. It is known that n<sub>P<sub>L</sub></sub> = 3.0 from earlier studies, and we identified n<sub>P<sub>lac</sub></sub> = 2.15 by our activity determination.
Image:Room_pressure_model.png|figure 5-2 Atmospheric pressure model. It is known that n<sub>P<sub>L</sub></sub> = 3.0 from earlier studies, and we identified n<sub>P<sub>lac</sub></sub> = 2.15 by our activity determination.
Image:30MPa_pressure_model2.png|figure 5-3 30MPa pressure model
Image:30MPa_pressure_model2.png|figure 5-3 30MPa pressure model
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<!--The kinetics of the genetic toggle switch is calculated from 'atmospheric pressure model' under atmospheric pressure while that is calculated from '30MPa pressure model' under 30MPa pressure.-->
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We used two differential equation models and we call them 'atmospheric pressure model' and '30MPa pressure model'.  
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[[Image:Desirable_condition.png|500px|thumb|left|fig5-4:Desirable condition<!--. left:under atmospheric pressure (nullclines of figure 5-2), right:under 30MPa pressure (nullclines of figure 5-3).-->]]
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In order to implement rewritable function, we decided to use the difference of nullclines of each system so as to satisfy the following condition
In order to implement rewritable function, we decided to use the difference of nullclines of each system so as to satisfy the following condition
* Converge to high CI concentration state under 30MPa pressure (writable)
* Converge to high CI concentration state under 30MPa pressure (writable)
* Bistable under atmospheric pressure (erasable)
* Bistable under atmospheric pressure (erasable)
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[[Image:Desirable_condition.png|500px|thumb|left|fig5-4:Desirable condition<!--. left:under atmospheric pressure (nullclines of figure 5-2), right:under 30MPa pressure (nullclines of figure 5-3).-->]]
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Revision as of 11:02, 26 October 2008

Home Construction Acrylic container Development of promoter Genetic toggle switch Parts Submitted to the Registry Result The Team Acknowledgements


Contents

Genetic toggle switch to implement rewritable function

In order to implement rewritable function, we tried to construct Pressure Inducible Genetic Toggle Switch (in short PIGTS). We thought two types of model - genetic circuit model and mathematical model - so as to construct PIGTS.

Genetic circuit model

figure 5-1 genetic circuit model

1. Writable function

  • Plac is induced under 30MPa pressure
  • Express CI and GFP
  • CI represses PL and causes low LacI concentration
  • Express increasingly CI and GFP(inserted destruction tags) ⇒ Bright!!


2. Erasable function

  • PL is induced by heat
  • Express LacI and LacI represses Plac
  • Therefore, GFP expression decreases

Mathematical model

Differential equation models

figure 5-2 Atmospheric pressure model. It is known that nPL = 3.0 from earlier studies, and we identified nPlac = 2.15 by our activity determination.

figure 5-3 30MPa pressure model

We used two differential equation models and we call them 'atmospheric pressure model' and '30MPa pressure model'. In order to implement rewritable function, we decided to use the difference of nullclines of each system so as to satisfy the following condition

  • Converge to high CI concentration state under 30MPa pressure (writable)
  • Bistable under atmospheric pressure (erasable)


fig5-4:Desirable condition



























Calculate the domain of appropriate parameters

fig5-5:The domain of appropriate parameters if αPlac = 3.0

It is known that Plac activity under 30MPa pressure is 94.0 times stronger than Plac activity under atmospheric pressure, so, β30Plac = 94.0. If 30MPa additional activity rate of PL (β30PL) or the ratio of Plac - RBS strength (αPlac) and PL-RBS strength(αPL) are not appropriate value, we can't construct PIGTS. So we calculated the domain of appropriate β30PL and the ratio of αPlac and αPL.


We identified β30PL = 1.42 by our experiment under 30MPa pressure. Therefore, we can implement rewritable function if we choose PL - RBS strength range from 2.4 to 7.4.

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