Part:BBa_K1992004

Tar expression system (promoter+RBS+coding+terminator)

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
  
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal AgeI site found at 1343
  
• 1000
  INCOMPATIBLE WITH RFC[1000]

  Illegal SapI.rc site found at 172
  

Introduction

Tar chemoreceptor is one of four native chemoreceptors of E.coli, it is mediate chemotaxis response towards aspartate and away from Ni and Co (1). This device allows the expression of a functionally native Tar chemoreceptor.

Usage and biology

This device constructed from strong promoter (BBa_J23100) and RBS (BBa_B0034) ensuring high expression of Tar chemoreceptor. High expression of a sole chemoreceptor increase the sensitivity of the bacteria to the substances that interacts with this receptor (2). This property makes the system efficient and useful even in low concentrations of ligands.

Experiments and results

In order to test the device it was cloned to chemoreceptor free strain (UU1250) and tested for chemotaxis ability using swarming assay. As can be seen in figure 1 the cells expressing the Tar chemoreceptor create a halo indicating a functional chemotaxis result, which compared to the negative and positive controls. The halo can be seen in a matter of hours ensuring that the halo is a result of a chemotaxis response. For more results and characterization of Tar chemoreceptor enter our [http://2016.igem.org/Team:Technion_Israel/Tar_improvements Tar improvment & characterization page]

Fig1. (a) Tar expression in UU1250 strain, resulting a halo indicating a functional chemotaxis response. (b) Negative control- UU1250 strain w/o the Tar expression plasmid. (c) positive control - ΔZ strain expressing all chemoreceptors.

Reference

1.BI, Shuangyu; LAI, Luhua. Bacterial chemoreceptors and chemoeffectors.Cellular and Molecular Life Sciences, 2015, 72.4: 691-708.
‏ 2.SOURJIK, Victor; BERG, Howard C. Functional interactions between receptors in bacterial chemotaxis. Nature, 2004, 428.6981: 437-441.‏