Overview & Purpose
- What this can be used for
- Sensing something
Basic Components of a Lac Operon
Natural Lac Operon Parts/DNA Schematic
The lac operon itself is a set of genes found in certain bacterias' DNA that is required for the transport and metabolism of lactose. Most commonly found in Escherichia coli, the operon was the first example of a group of genes under the control of an operator region to which a lactose repressor binds.
The lac operon functions as a single transcription unit and is comprised of an operator, a promoter, and on or more structural genes such as a regulator or terminator that are transcribed into one polycistronic mRNA. When the bacteria are transferred to lactose-containing medium, allolactose (which forms when lactose is present in the cell) binds to the repressor, inhibits the binding of the repressor to the operator, and allows transcription of mRNA for enzymes involved in lactose metabolism and transport across the membrane.
Design: Our genetic circuit
OUR GENE SWITCH:
<tab>pSB1A3-1 is a high copy number plasmid. The replication origin is a pUC19-derived pMB1 (copy number of 100-300 per cell). The terminators bracketing pSB1A3 MCS are designed to prevent transcription from inside the MCS from reading out into the vector.
Building: Assembly Scheme
Testing: Modeling and GFP Imaging
A LAC SWITCH MODEL
We used a previously published synthetic switch, developed by Ceroni et al., to understand how our system could potentially be modeled and simulated.
AN INTERACTIVE MODEL
We used a model of the natural Lac operon to understand how changing the parameter values changes the behavior of the system.
COLLECTING IMPERICAL VALUES TO IMPROVE THE MODEL
We explored how one technique, imaging via microscopy could be used to determine the production rate of an output protein, in this case GFP in yeast, could be used to determine a "real" value for maximum GFP production rate under our own laboratory conditions.
- show plot of data and discuss outcome.
- include some of the pictures of the raw data
- wrap up section to explain how the curves could be improved
Ideally, the GFP production rate measured by this method could be entered as a value for [which parameter] in the Ceroni et al. model.
Danger of Chemicals in Farmlands
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