Difference between revisions of "Team:Tokyo Tech/Model"

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    <div class="floating"><img src="https://static.igem.org/mediawiki/2016/1/1f/T--Tokyo_Tech--Population-miss.png" height ="300" class="align_left">
 
    <div class="floating"><img src="https://static.igem.org/mediawiki/2016/1/1f/T--Tokyo_Tech--Population-miss.png" height ="300" class="align_left">
    <p class="caption" style="font-size: 16px; text-align: center;"><span style="font-weight: bold;">Fig.5-4-2-1. Number of individuals when the Prince <span style ="font-style : italic">coli</span> is introduced from the beginning</span></p></div>
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    <p class="caption" style="font-size: 16px; text-align: center;"><span style="font-weight: bold;">Fig.5-4-1-1. Number of individuals when the Prince <span style ="font-style : italic">coli</span> is introduced from the beginning</span></p></div>
 
    <div class="floating"><img src="https://static.igem.org/mediawiki/2016/f/f1/T--Tokyo_Tech--AHL-miss.png" height ="300" class="align_right">
 
    <div class="floating"><img src="https://static.igem.org/mediawiki/2016/f/f1/T--Tokyo_Tech--AHL-miss.png" height ="300" class="align_right">
    <p class="caption" style="font-size: 16px; text-align: center;"><span style="font-weight: bold;">Fig.5-4-2-2. AHL concentrations when the Prince <span style ="font-style : italic">coli</span> is introduced from the beginning</span></p></div>
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    <p class="caption" style="font-size: 16px; text-align: center;"><span style="font-weight: bold;">Fig.5-4-1-2. AHL concentrations when the Prince <span style ="font-style : italic">coli</span> is introduced from the beginning</span></p></div>
  
                   <p class="normal_text">As a result, if we introduce the Prince <span style ="font-style : italic">coli</span> from the beginning, the number of Prince <span style ="font-style : italic">coli</span> increases too much (Fig.5-4-2-1) so the AmiE the Prince <span style ="font-style : italic">coli</span> produces augments and the decomposition of C12 also occurs overly. So C12 is almost inexistent in the medium (Fig.5-4-2-2).</p>
+
                   <p class="normal_text">As a result, if we introduce the Prince <span style ="font-style : italic">coli</span> from the beginning, the number of Prince <span style ="font-style : italic">coli</span> increases too much (Fig.5-4-1-1) so the AmiE the Prince <span style ="font-style : italic">coli</span> produces augments and the decomposition of C12 also occurs overly. So C12 is almost inexistent in the medium (Fig.5-4-1-2).</p>
  
 
                   <div class="floating"><img src="https://static.igem.org/mediawiki/2016/e/e7/T--Tokyo_Tech--Population.png" height ="300" class="align_left"><br>
 
                   <div class="floating"><img src="https://static.igem.org/mediawiki/2016/e/e7/T--Tokyo_Tech--Population.png" height ="300" class="align_left"><br>
    <p class="caption" style="font-size: 16px; text-align: center;"><span style="font-weight: bold;">Fig.5-4-2-3. Number of individuals when the Prince <span style ="font-style : italic">coli</span> is introduced at t = 700</span></div>
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    <p class="caption" style="font-size: 16px; text-align: center;"><span style="font-weight: bold;">Fig.5-4-1-3. Number of individuals when the Prince <span style ="font-style : italic">coli</span> is introduced at t = 700</span></div>
 
    <div class="floating"><img src="https://static.igem.org/mediawiki/2016/4/4f/T--Tokyo_Tech--AHL.png" height ="300" class="align_right"><br>
 
    <div class="floating"><img src="https://static.igem.org/mediawiki/2016/4/4f/T--Tokyo_Tech--AHL.png" height ="300" class="align_right"><br>
    <p class="caption" style="font-size: 16px; text-align: center;"><span style="font-weight: bold;">Fig.5-4-2-4. AHL concentrations when the Prince <span style ="font-style : italic">coli</span> is introduced at t = 700</span></div>
+
    <p class="caption" style="font-size: 16px; text-align: center;"><span style="font-weight: bold;">Fig.5-4-1-4. AHL concentrations when the Prince <span style ="font-style : italic">coli</span> is introduced at t = 700</span></div>
  
                   <p class="normal_text">On the other hand, if we introduce the Prince <span style ="font-style : italic">coli</span> at t = 600, the number of Prince <span style ="font-style : italic">coli</span> does not increment much (Fig.5-4-2-3), so C12 can exist until t = 600 and then decreases thanks to the augment of AmiE (Fig.5-4-2-4).<br>In conclusion, if we introduce the Prince <span style ="font-style : italic">coli</span> at t = 700, the circuit will behave accordingly.</p>
+
                   <p class="normal_text">On the other hand, if we introduce the Prince <span style ="font-style : italic">coli</span> at t = 600, the number of Prince <span style ="font-style : italic">coli</span> does not increment much (Fig.5-4-1-3), so C12 can exist until t = 600 and then decreases thanks to the augment of AmiE (Fig.5-4-1-4).<br>In conclusion, if we introduce the Prince <span style ="font-style : italic">coli</span> at t = 700, the circuit will behave accordingly.</p>
 
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<p class="normal_text">In order to confirm the feasibility of the story with our gene circuit by the combination of the existing promoters, we performed some simulations based on the results of our assays.</p>
 
<p class="normal_text">In order to confirm the feasibility of the story with our gene circuit by the combination of the existing promoters, we performed some simulations based on the results of our assays.</p>
 
<div align="center"><img src="https://static.igem.org/mediawiki/2016/6/68/T--Tokyo_Tech--projct_model1.png" height ="450"><br></div>
 
<div align="center"><img src="https://static.igem.org/mediawiki/2016/6/68/T--Tokyo_Tech--projct_model1.png" height ="450"><br></div>
<div align="center"><p class="caption" style="font-size: 16px; text-align: center;"><span style="font-weight: bold;">Fig.5-4-3. The intensity of Plux and Prhl promoters</span>
+
<div align="center"><p class="caption" style="font-size: 16px; text-align: center;"><span style="font-weight: bold;">Fig.5-4-2. The intensity of Plux and Prhl promoters</span>
 
                   <p class="normal_text">The diagram above shows that the intensity of the two promoters should be in the red region of the figure.The combination of promoters which we were originally going to use is shown in the graph by the green point. To move this point into the red region, we had to improve Prhl to raise its expression level.</p>
 
                   <p class="normal_text">The diagram above shows that the intensity of the two promoters should be in the red region of the figure.The combination of promoters which we were originally going to use is shown in the graph by the green point. To move this point into the red region, we had to improve Prhl to raise its expression level.</p>
 
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<p class="normal_text">We performed the sensitivity analysis descried in this section in order to examine which parameter dominates the story. We defined these requirements as the “successful Snow White story.”<br>
 
<p class="normal_text">We performed the sensitivity analysis descried in this section in order to examine which parameter dominates the story. We defined these requirements as the “successful Snow White story.”<br>
 
1) At t = 150<br>
 
1) At t = 150<br>
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<p class="normal_text">The signaling molecule production rates by RhlI and LasI can be changed by modifying RhlI and LasI to make more or less signaling molecule in silico.</p>
 
<p class="normal_text">The signaling molecule production rates by RhlI and LasI can be changed by modifying RhlI and LasI to make more or less signaling molecule in silico.</p>
  
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<p class="normal_text">Translation rate affects the production of protein.</p>
 
<p class="normal_text">Translation rate affects the production of protein.</p>
 
 
<div align="center"><img src="https://static.igem.org/mediawiki/2016/0/03/T-Tokyo_Tech--Translation.png" height ="450"><br></div>
 
<div align="center"><img src="https://static.igem.org/mediawiki/2016/0/03/T-Tokyo_Tech--Translation.png" height ="450"><br></div>
 
<div align="center"><p class="caption" style="font-size: 16px; text-align: center;"><span style="font-weight: bold;">Fig.5-4-5. Concentrations of GFP and RFP dependencies of translation rate of proteins</span>
 
<div align="center"><p class="caption" style="font-size: 16px; text-align: center;"><span style="font-weight: bold;">Fig.5-4-5. Concentrations of GFP and RFP dependencies of translation rate of proteins</span>
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<p class="normal_text">AmiE decomposes C12. The concentration of C12 after input of the Prince <span style ="font-style : italic">coli</span> is changed by AmiE. If the decomposition rate of C12 is too small, C12 does not decrease enough so the MazF inside Snow White <span style ="font-style : italic">coli</span> continues being expressed and the concentration of RFP decreases.</p>
 
<p class="normal_text">AmiE decomposes C12. The concentration of C12 after input of the Prince <span style ="font-style : italic">coli</span> is changed by AmiE. If the decomposition rate of C12 is too small, C12 does not decrease enough so the MazF inside Snow White <span style ="font-style : italic">coli</span> continues being expressed and the concentration of RFP decreases.</p>
  
 
<div align="center"><img src="https://static.igem.org/mediawiki/2016/0/08/T--Tokyo_Tech--Decomposition.png" height ="450"><br></div>
 
<div align="center"><img src="https://static.igem.org/mediawiki/2016/0/08/T--Tokyo_Tech--Decomposition.png" height ="450"><br></div>
 
<div align="center"><p class="caption" style="font-size: 16px; text-align: center;"><span style="font-weight: bold;">Fig.5-4-6. Concentrations of GFP and RFP dependencies of decomposition rate of C12 by AmiE</span>
 
<div align="center"><p class="caption" style="font-size: 16px; text-align: center;"><span style="font-weight: bold;">Fig.5-4-6. Concentrations of GFP and RFP dependencies of decomposition rate of C12 by AmiE</span>
 
 
                   <p class="normal_text">Each line corresponds to the transition of the concentration of RFP and GFP with a certain decomposition rate of C12. Red and green lines correspond to RFP and GFP, respectively. Blighter one indicates higher value of decomposition rate of C12.<br>
 
                   <p class="normal_text">Each line corresponds to the transition of the concentration of RFP and GFP with a certain decomposition rate of C12. Red and green lines correspond to RFP and GFP, respectively. Blighter one indicates higher value of decomposition rate of C12.<br>
 
                   If degradation rate of C12 is higher than 0.00056, our system can recreate the story.</p>
 
                   If degradation rate of C12 is higher than 0.00056, our system can recreate the story.</p>
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<p class="normal_text">The degradation rate of RFP and GFP is key to the success the story of ‘"Snow White".<br>
 
<p class="normal_text">The degradation rate of RFP and GFP is key to the success the story of ‘"Snow White".<br>
 
These parameters are closely related to the concentrations of GFP and RFP, so we conjectured that if they do not take appropriate values the story can not be correctly recreated.</p>
 
These parameters are closely related to the concentrations of GFP and RFP, so we conjectured that if they do not take appropriate values the story can not be correctly recreated.</p>
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                   <p class="normal_text">The story is recreated only if the degradation rate of RFP and GFP are the same.</p>
 
                   <p class="normal_text">The story is recreated only if the degradation rate of RFP and GFP are the same.</p>
 
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Revision as of 17:54, 19 October 2016

1. Overview

To recreate the story of ”Snow White”, we have designed a cell-cell communication system with improved or characterized parts and collected data from comprehensive experiments. Furthermore, we constructed the mathematical model to simulate the behavior of the whole system and to confirm the feasibility of our story. This simulation successfully contributed to give the suggestions to wet lab experiments. In addition, in order to help us utilize our Toxin-Antitoxin (TA) system, we developed a new software in Java for adjusting the number of ACA sequences, which MazF dimer recognizes and cleaves in mRNAs.

2. Story simulation

2-1. Mathematical model

In order to simulate our gene circuits, we developed an ordinary differential equation model.

[Model development]


2-2. Results

We obtained and confirmed the desirable behavior of the whole system by modifying and improving parts. As described below, our simulation showed an appropriate transition of concentration of RFP and GFP for the story.


Fig.5-2. Time-dependent change of the concentrations of fluorescence proteins


In the blue area of Fig.5-2-2, the concentration of fluorescence proteins starts to increase. The concentration of RFP of Snow White coliexceeds the concentration of GFP of the Queen coli.
It is as if Snow White got fairer more and more.

In the pink area of Fig.5-2-2, C12 is being synthesized and increased thanks to the appearance of C4. As a result, the MazF inside Snow White coli and the Queen coli, suppressing the increment of fluorescent proteins.
It is as if the Queen, influenced by the Mirror's answer, transforming into a Witch in order to give Snow White a poisoned apple.

In the green area of Fig.5-2-2, C12 increases and the MazF inside Snow White coli induced by it increases even more. So the concentration GFP exceeds that of RFP.
It looks as if Snow White bit the apple, sinking into unconsciousness promptly.

In the yellow area of Fig.5-2-2, the AmiE synthesized by the introduced the Prince coli decomposes C12 so the MazF inside Snow White coli diminishes and C4 increases.
It looks as if the Prince lifted Snow White and she opened her eyes.

3. Fitting

3-1. Population growth

First, we tried to model the growth curve of the system. When the number of E. coli approaches a certain value, the growth will stop. We defined this value in the culture as Pmax. Then the population growth equation for our system is described as follows:
$$ \frac{dP}{dt} = g\left(1 - \frac{P}{P_{max}}\right)P$$
where g is the population growth rate.
This equation can be analytically solved as:
$$ P = \frac{P_{0} P_{max} e^{gt}}{P_{max} - P_{0} + P_{0} e^{gt}}$$
where P 0 is the population at t = 0. We used this equation to fit the experimental data.


Fig.5-3-1. Modeled growth curve of E. coli fitted to experiment data

Using the experimental data from the Toxin assay for this fitting, we estimated the following parameters:

g = 0.0123
and
Pmax =3.3

respectively.
These parameters can be used for Snow White coli, the Queen coli and the Prince coli in the same way.

3-2. Toxin-Antitoxin system

3-3. Promoters

3-4. More realistic model with mRNA

4. Analysis

4-1. The Prince coli should be put in during the process

We run simulations in order to determine whether we would get a better behavior let we introduce the Prince coli at the beginning or halfway of the story.

Fig.5-4-1-1. Number of individuals when the Prince coli is introduced from the beginning

Fig.5-4-1-2. AHL concentrations when the Prince coli is introduced from the beginning

As a result, if we introduce the Prince coli from the beginning, the number of Prince coli increases too much (Fig.5-4-1-1) so the AmiE the Prince coli produces augments and the decomposition of C12 also occurs overly. So C12 is almost inexistent in the medium (Fig.5-4-1-2).


Fig.5-4-1-3. Number of individuals when the Prince coli is introduced at t = 700


Fig.5-4-1-4. AHL concentrations when the Prince coli is introduced at t = 700

On the other hand, if we introduce the Prince coli at t = 600, the number of Prince coli does not increment much (Fig.5-4-1-3), so C12 can exist until t = 600 and then decreases thanks to the augment of AmiE (Fig.5-4-1-4).
In conclusion, if we introduce the Prince coli at t = 700, the circuit will behave accordingly.


4-2. Prhl should be changed

In order to confirm the feasibility of the story with our gene circuit by the combination of the existing promoters, we performed some simulations based on the results of our assays.


Fig.5-4-2. The intensity of Plux and Prhl promoters

The diagram above shows that the intensity of the two promoters should be in the red region of the figure.The combination of promoters which we were originally going to use is shown in the graph by the green point. To move this point into the red region, we had to improve Prhl to raise its expression level.


4-3. Requirements


4-4. Production rate of C4HSL and 3OC12HSL by RhlI and LasI


4-5. Translation rate of protein


4-6. Decomposition rate of C12 by AmiE


4-7. Degradation rate of AmiE


4-8. Degradation rate of RFP and GFP

5. Software


5-1. Abstract


We developed a new software named ACADwarfs. This software helps to control the sensitivity of the protein to MazF by regulating the number of ACA sequences in the mRNA sequence. ACADwarfs can increase or decrease the number of ACA sequences on mRNA without changing the amino acid sequences that the mRNA specifies or frameshifts resulted from insertion of bases without considering.
Then we improve the practicality of the characteristic of the mazEF system. For example you can let protein A express constantly by eliminating ACA sequences of the sequence, while letting protein B stop being expressed, at the desirable timing, by expression of MazF.
This software also evades the use of rare codons, so you don’t have to worry about them.


5-2. Key achievements

・Provided the tool regulating the number of ACA sequences

・Released under open-source license so everyone can use it

・Able to correspond to any base arrangements

・Rare codons are evaded

・Extend the application field of mazEF system


5-3. Work flow

  1. Start ACADwarfs

    Download the zip file and open it.

  2. Put in the part sequence

    Put the part sequence you want to regulate the effect of the mazEF system on in the upper window.

  3. Choose operation

    If you want to magnify the effect of mazEF system, choose “increase ACA”.

    If you want to lessen the effect of mazEF system, choose “decrease ACA”.

  4. Get sequences

    You can get the modified part sequences in the lower window. Modified codons will be written in capital letters and while the rest will be in small letters so you can easily locate the modified parts.
    And under this window you can see the number of ACA sequences on the sequence before the modification of the following "previous number" and the number of ACA sequences on the sequence after the modification of the following "new number".


5-4. Demonstration

We created a demo to present the features of this software. Using this, we regulated the number of ACA sequences and control the sensitivity of the protein to MazF.

Gene Pre number of ACA sequences Post number of ACA sequences
RFP 10 30
GFP 23 39
MazF 2 1
MazE 2 1

We increased the numbers of ACA sequences of RFP and GFP decreased the numbers of ACA sequences of MazF and MazE .


Fig.5-4. Comparison between the results of simulations using original sequences and modified sequences

We can see that the concentration of expressed MazF reacts more keenly after adjusting the ACA sequences than before doing so.


5-5. Download

To download click here.

The code is available on github.