Team:CIDEB-UANL Mexico/project resistance


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iGEM CIDEB 2014 - Project

Resistance Module

Because our project is a biofilter which allows to remove salt from water, the bacteria needs to survive to extreme environmental conditions which normally it can’t do. We need E. Coli to survive a high salinity environment to allow it to capture sodium ions and to remove the salt concentration of the water.

In order to accomplish our project goal, we have to change E. Coli metabolism and make it stronger, more resistant and more efficient than in normal E.coli bacteria.

Last discoveries show irrE as a protein capable of change the E. Coli metabolism, and giving it the ability to survive to bigger temperatures, bigger UV rays radiation and bigger salt concentration (UCL, 2012).

What does irrE do?

The protein irrE originates from Deinococcusradiodurans, and initially, this gene provides resistance to radiation. But when transformed in E. Coli, it protects it against salt, oxidative and thermal shock. (UCL, 2012) Also, different experiments from different iGEM teams, support the idea of the bigger salt resistance in E. Coli with this biobrick.


Image 1. This graph done by UCL iGEM 2012, shows how irrE biobrick increased the salt concentration resistance in E. Coli compared with the results from Tu Delf iGEM 2010.

How it works?

irrE has been demonstrated to up regulate transcription of recA and pprA - genes which encode Recombines A and Radiation Inducible Protein. With respect to salt tolerance, irrE up regulates the production of several stress responsive proteins, protein kinases, metabolic proteins, and detoxification proteins. It also down regulates glycerol degradation. With this global regulatory effect, E. Coli becomes more salt tolerant (UCL, 2012).


Image 2. This diagram shows the effect of irrE protein on E. Coli metabolism.

Other teams that used it:

UCL 2012: They propose to confer salt tolerance on E. Coli by linking the salt tolerance gene encoding the protein irrE (BBa_K729001) to a constitutive promoter (BBa_J23119).


Image 3. Part designed by UCL 2012 for the irrE protein.

irrE's parts description :







In the specific case of our bacteria, it helps to continuously transcribing the irrE gene in order to make bacteria resist high concentration of salt. This promoter has a length of 35 pb(Anderson, 2006).




This specific is RBS based on Elowitz repressilator. It is very common to see in many iGEM projects.  It has a length of 12 pb (Mahajan, Marinescu, Chow, Wissner-Gross, & Carr, 2003).


Gene that produces irrE, a substance that changes the bacteria’s metabolism and allows bacteria to survive to extreme conditions, some examples could be high UV rays exposition, or high salt concentration levels in an aquatic environment, oxidative or thermal shock.  It has a length of 933pb (Sohrabi, 2012).



Part made of 6pb responsible for transcription stop (Huang, 206).


● Antiquity 2013. (2013, January 31). Part:BBa_B0034. Retrieved from

● Huang, H. (2006, August 30). Part:BBa_B1002. Retrieved August 30, 2014, from

● iGEM2006_Berkeley. (2006, August 24). Part:BBa_J23119. Retrieved April 30, 2014, from

● Sohrabi, B. (2012, June 27). Part:BBa_K729001. Retrieved from

● UCLiGEM Team. (2012). IRRE module. Retrieved March 31, 2014. from

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