Team:BrownTwo/Limiter/intro

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Latest revision as of 01:06, 30 October 2008

Threshold Regulation

Threshold limitation

In the early days of radio, AM transmitters were vulnerable to overload by an input signal of too great a magnitude. To protect the transmitter from damage, a limiter circuit was employed to attenuate signal peaks while allowing all subthreshold signal to pass through unchanged. We have designed a genetic circuit that behaves similarly. Our gene network reacts to the level of transcription of a gene of interest, limiting it to levels above or below a user-defined threshold. In our proof-of-concept, we use synthetic transcription factors to limit the expression of an inducible reporter. In practice, these modular transcription factors can be used to regulate any endogenous gene with a known promoter and transcription factor DNA-binding domain. Extremes of gene expression can damage living systems, while normal expression is healthy. Our limiter could react to the level of a gene's expression within individual cells, correcting problems only where and when they occur.

An Electronic Limiter Circuit

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 {{limitertemp}}
-==''The Utility of Threshold Regulation''==
+==''Threshold Regulation''==
-<br>
-:<p>In the early days of radio, AM transmitters were vulnerable to overload by an input signal of too great a magnitude.  To protect the transmitter from damage, a limiter circuit was employed to attenuate signal peaks while allowing all subthreshold signal to pass through unchanged.  We have designed a genetic circuit that behaves similarly.  Our gene network reacts to the level of transcription of a gene of interest, limiting it to levels above or below a user-defined threshold.  In our proof-of-concept, we use synthetic transcription factors to limit the expression of an inducible reporter.  In practice, these modular transcription factors can be used to regulate any endogenous gene with a known promoter and transcription factor DNA-binding domain.  Extremes of gene expression can damage living systems, while normal expression is healthy.  Our limiter could react to the level of a gene's expression within individual cells, correcting problems only where and when they occur.</p>
 <br>
+[[Image:thresh.png|center|thumb|240px|Threshold limitation]]
-[[Image:Limiter_history.jpg|center|thumb|500px|Limiter of the good ol' days]]
+<p>In the early days of radio, AM transmitters were vulnerable to overload by an input signal of too great a magnitude.  To protect the transmitter from damage, a limiter circuit was employed to attenuate signal peaks while allowing all subthreshold signal to pass through unchanged.  We have designed a genetic circuit that behaves similarly.  Our gene network reacts to the level of transcription of a gene of interest, limiting it to levels above or below a user-defined threshold.  In our proof-of-concept, we use synthetic transcription factors to limit the expression of an inducible reporter.  In practice, these modular transcription factors can be used to regulate any endogenous gene with a known promoter and transcription factor DNA-binding domain.  Extremes of gene expression can damage living systems, while normal expression is healthy.  Our limiter could react to the level of a gene's expression within individual cells, correcting problems only where and when they occur.</p>
+<br>
-Our limiter device represents an example of a complex device built from smaller parts and circuits available to synthetic biology.  At the same time, however, it also constitutes a departure from the iGEM tradition of building devices that function solely in a bacterial chassis.
+[[Image:Limiter_history.jpg|center|thumb|450px|An Electronic Limiter Circuit]]