Part:BBa_K2315034

LasR-pLas-GFP HSL inducible fluorescent actuator

Group: Shanghaitech iGEM 2017

The AHL receiver LasR from P.aeruginosa activates expression of GFP protein in response to 3OC12-HSL.

This Receiver can be easily replaced by other AHL receivers in our collection. A full collection could be found in: http://2017.igem.org/Team:Shanghaitech/Library

Usage and Biology

Fig. 1 Genetic Circuit Design

When AHL is added with concentration higher than a critical value, the constitutively expressed LasR will bind to the AHL molecule 3OC12-HSL, dimerize and bind to the pLas regulatory sequence to activate GFP expression.

Fluorescent Response to cognate 3OC12-HSL

To test this part, we used standard 3OC12HSL (HSL produced by LasI in P.aeruginosa) to determine the response curve.

Fig. 1 LasR-pLas-GFP‘s response to cognate 3OC12HSL

Orthogonality test against non-cognate inducers

We have characterized crosstalk response of LasR to several non-cognate AHLs:

Fig. 2 Orthogonality test of LasR-pLas-GFP (i):Fluorescent response to cognate and non-cognate AHLs (ii)Dose-Response curves for cognate and non-cognate AHLs (iii-vi)Fluorescent response to non-cognate AHLs in compared with 3OC12-HSL

Furthermore, we test it under fluorescence microscope. Fig. 3 shows four testing samples.

Fig. 3 Orthogonality test under fluorescence microscope a) Interlab Study Test Device 1 BBa_J364000 b) Las molecule 3OC12-HSL as inducer c) Tra molecule 3OC8-HSL as inducer d) Rpa molecule Coumaroyl-HSL as inducer

It has shown that LasR is sensitive to it's cognate HSL and has obvious crosstalk with 3OC8-HSL in Tra System in relatively high concentration.

Usages in our Project

We developed a measurement protocol using the fluorescent protein coupled AHL receiver germs to measure the actual AHLs concentration in high precision and sensitivity in compared with LC-MS.

AHL receiver from P.aeruginosa, actives expression of GFP protein.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  INCOMPATIBLE WITH RFC[12]

  Illegal NheI site found at 7
  Illegal NheI site found at 30
  Illegal NheI site found at 979
  
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 375
  Illegal AgeI site found at 572
  
• 1000
  INCOMPATIBLE WITH RFC[1000]

  Illegal BsaI.rc site found at 1740