View source for Chassis/Cell-Free Systems

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=Cell-Free Systems=

==Introduction==
'''Cell-Free Systems (CFS)''' involve the in-vitro expression of genes into proteins. These systems can serve as a compatible chassis for the various parts and devices from the Registry of Standard Biological Parts.

Coupled transcription-translation systems usually combine a bacteriophage RNA polymerase and promoter with eukaryotic or prokaryotic extracts. In addition, the PURE system has been developed as a reconstituted CFS for synthesizing proteins using recombinant elements.
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'''Advantages and disadvantages of CFS'''
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|width=50%|<center>'''Advantages'''</center>
|width=50%|<center>'''Disadvantages'''</center>
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|style="background:#eeffee"|Non-infectious because of non-proliferative nature
|style="background:#ffeeee"|Short expression lifespan since system cannot replicate
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|style="background:#eeffee"|Process is quick and simple requiring only preparation of cell extract and feeding solution and subsequent addition of DNA template
|style="background:#ffeeee"|Expensive because of the constant need for nutrient and energy supply
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|style="background:#eeffee"|Quality control can be achieved easily using modified reaction conditions such as addition of accessory elements or inhibitory factors
|style="background:#ffeeee"|Less characterization and experience of use in the laboratories compared to ''E. coli''
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'''Specifications for CFS characterization'''<br>
The following are several parameters that will help us understand the advantages and disadvantages associated with a particular chassis housing the gene expression machinery.
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|style="background:#ffffcc"|'''Properties'''
||<center>'''Definitions'''</center>
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|style="background:#ffffcc"|Rise time
||Measure of time from start of reaction to the point when expression rate first reaches the steady state value.
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|style="background:#ffffcc"|Peak time
||Measure of time from start of reaction to the point when expression rate reaches the maximum value.
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|style="background:#ffffcc"|Settling time
||Measure of time from start of reaction to the point when expression rate reaches the steady state and does not escape from it for a prolonged period of time.
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|style="background:#ffffcc"|Stability of synthesized protein
||Measure of the half-life of a given protein (e.g. GFP) in the chassis.
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|style="background:#ffffcc"|Total expression capacity
||Measure of the total expression of a chassis for a given DNA construct template. This should take into account the degradation of synthesized protein.
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|style="background:#ffffcc"|Expression lifespan
||Measure of time that expression occurs for a given DNA construct template until protein degradation overrides protein synthesis.
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==Cell-Free Systems investigated==

*[[Chassis/Cell-Free_Systems/Commercial_E.Coli_T7_S30_extract | Home-made E.Coli T7 S30 Extract]]
*[[Chassis/Cell-Free_Systems/Home made_E.Coli_S30_extract | Home made E.Coli S30 Extract]]
*[[Chassis/Cell-Free_Systems/Commercial_E.Coli_S30_extract | Commercial E.Coli S30 Extract]]
* Vesicles ...




==References==

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