Team:Paris Bettencourt/Project/Phage Sensor

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Phage Sensor

Overview

We develop a sensor to target antibiotic resistances in tuberculosis to test if a specific strain carries a certain antibiotic resistance. Our sensor system consists out of a phagemid with a CRISPR/Cas system and LacZ as a reporter under the control of a pREC promoter (the promoter of the RecA protein that is involved in the stress response of bacteria). If our CRISPR/Cas system can now bind to the target (antibiotic resistance gene), the Cas9 generates at this specific target site a double strand break, which then starts the expression of our reporter, as the promoter gets active at stress that results from double strand breaks. Because our system is on a phagemid, the sensor system will be spread all over the population, which will give a clear color output if the target has been detected. This means, depending on what target sequence our system carries, we can identify the different antibiotic resistances that a strain might carry. This is a novel way of detecting resistances in bacterial strains. As a proof of concept we will use E.coli to target KanR. The used phage will be M13. This sensor could potentially be used to test if a patient has TB and what type of resistance genes the specific strain contains to adapt drug treatment.


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Producer bacteria

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Phagemid is packed into the capsid, produced by the helper plasmid

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Phagmids are isolated

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Phagmids are mixed with target bacteria

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Right species?
Yes, Phagemids enter the cell


06.jpg
Expression of CrRNA, tracerRNA and Cas9
Processing of CrRNA + tracerRNA


07.jpg
Fusion of Cas9 and hybrid RNA complex

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Antibiotic resistance of interest there?
Yes : Cas9 - RNA complex bind to target sequence


09.jpg
Cas9 generates double strand break
pRech-SOS response activated
LacZ is expressed


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ß-galactosidase hydrolisis Xgal : blue cells appear

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Centre for Research and Interdisciplinarity (CRI)
Faculty of Medicine Cochin Port-Royal, South wing, 2nd floor
Paris Descartes University
24, rue du Faubourg Saint Jacques
75014 Paris, France
+33 1 44 41 25 22/25
team2013@igem-paris.org
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