Tokyo/Requirements

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(What is necessary for "Balanced differentiation"?)
(2. Cell-cell communication)
 
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== What is necessary for "Balanced differentiation"? ==
== What is necessary for "Balanced differentiation"? ==
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The most important and underlying point of our model is that the system is stable against environmental changes when two types of differentiated individuals coexist, called "Balanced differentiation." Our project have aimed at this "Balanced differentiation" but not dynamic equilibrium such as chemical ones.   
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The most important and underlying point of our model is that the system is stable against environmental changes when two types of differentiated individuals coexist, called "Balanced differentiation." Our project has aimed at this "Balanced differentiation" but not dynamic equilibrium such as chemical ones.   
<!--共存安定をなりたたせるために必要な要素は以下の3つである
<!--共存安定をなりたたせるために必要な要素は以下の3つである
1.双安定
1.双安定
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3.2つの機能が1つの細胞から実現されること-->
3.2つの機能が1つの細胞から実現されること-->
<br>To achieve this “Balanced differentiation", our model requires
<br>To achieve this “Balanced differentiation", our model requires
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<br>1. differentiation(=bistability) generated by mutural-inhibition circuit.  
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<br>1. differentiation(=bistability) generated by mutual-inhibition circuit.  
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<br>2. cell-cell communication by quarum sensing
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<br>2. cell-cell communication by quorum sensing
   
   
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[[Image:Bistability.JPG|thumb|250px| '''Fig.1: Bistablity''' <br>Cells with the same gene take either of two differentiated states, A (worker, red) or B (idler, green) stably.]]
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[[Image:Stable.jpg|thumb|250px| '''Fig.1: Differentiation(=bistability)''' <br>Cells with the same gene take either of two differentiated states, A (worker, red) or B (idler, green) stably.]]
<!--それぞれについて以下で説明する。-->
<!--それぞれについて以下で説明する。-->
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====1. differentiation(=bistability)====
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====1. Differentiation(=bistability)====
<!--これがないと、動的平衡になってしまう。<br>Without this, our model is subject to dynamic equilibrium.-->
<!--これがないと、動的平衡になってしまう。<br>Without this, our model is subject to dynamic equilibrium.-->
'''~ at an individual level ~'''
'''~ at an individual level ~'''
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====2. Cell-cell communication ====
====2. Cell-cell communication ====
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When this balanced differentiation is disrupted, by removing all the A type for example, these individual cells sense the change. Their states A or B become unstable as if cells became upset - '''INDIVIDUAL STATES ARE UNSTABLE ⇒ They are COLLECTIVELY UNSTABLE'''. Then some of them changed their states while the others do not. As a result, at a certain ratio of A and B again, the whole system comes back to a stable states. Here the cells are '''COLLECTIVELY STABLE ⇒ INDIVIDUALS ARE STABLE''' under this balanced differentiation.
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When this balanced differentiation is disrupted, by removing all the A types for example, the rest individual B cells sense the change. Their differentiated states become unstable as if they become upset. Then all cells dedifferentiate, but after a while, redifferentiation is triggered by cell-cell communication. As a result, at a certain ratio of A and B again, the whole system comes back to a stable state.
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[[Image:cellcell.jpg|thumb|450px| '''Fig.2: Cell-cell communication'''<br>Intercellular interaction is done by communication molecule AHL. When enough AHL is produced by the workers, the idlers are stable; however, if it is not ~ communication being interrupted, ~ they dedifferentiate. Thus, cells can sense the surrounding cell types. ]]
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[[Image:Cellcell.JPG|thumb|450px| '''Fig.2: Cell-cell communication'''<br>Intercellular interaction is established by communication molecule AHL. When enough AHL is produced by the workers, the idlers are stable; however, if it is not ~ communication being interrupted, ~ they dedifferentiate. Thus, cells can sense the surrounding cell types. ]]

Latest revision as of 05:06, 27 October 2007


Abstract  Concept & Model  Requirements  Genetic_circuit  Works  About_our_team

What is necessary for "Balanced differentiation"?

The most important and underlying point of our model is that the system is stable against environmental changes when two types of differentiated individuals coexist, called "Balanced differentiation." Our project has aimed at this "Balanced differentiation" but not dynamic equilibrium such as chemical ones.
To achieve this “Balanced differentiation", our model requires
1. differentiation(=bistability) generated by mutual-inhibition circuit.
2. cell-cell communication by quorum sensing


Fig.1: Differentiation(=bistability)
Cells with the same gene take either of two differentiated states, A (worker, red) or B (idler, green) stably.


1. Differentiation(=bistability)

~ at an individual level ~

For "balanced differentiation" in our model, two types of cells should coexist stably. Therefore, cells with THE SAME GENE SET need to take either of TWO DIFFERENTIATED STATES, A (Worker) or B (Idler) in our project as shown in Fig. 1. In order to distinguish from dynamic stability, "balanced differentiation" must be achieved by two distinct states inconvertible each other. This bistability can be achieved by mutual-inhibition circuit.




2. Cell-cell communication

When this balanced differentiation is disrupted, by removing all the A types for example, the rest individual B cells sense the change. Their differentiated states become unstable as if they become upset. Then all cells dedifferentiate, but after a while, redifferentiation is triggered by cell-cell communication. As a result, at a certain ratio of A and B again, the whole system comes back to a stable state.

Fig.2: Cell-cell communication
Intercellular interaction is established by communication molecule AHL. When enough AHL is produced by the workers, the idlers are stable; however, if it is not ~ communication being interrupted, ~ they dedifferentiate. Thus, cells can sense the surrounding cell types.