Part:BBa_K4656010

PRM-CI857-PR-phIF-MazE-PphIF-MazF

The temperator-sensitive lambda CI repressor protein has a CI⁸⁵⁷ mutation, and when the temperature is reduced to 30℃, CI⁸⁵⁷ converges to synthesize a dimer, binds to the promoter PR and inhibits it, resulting in suppression of downstream phIF expression. The lowered phIF expression can not inhibit the promoter PphIF anymore and the toxin MazF downstream of it disengaged from inhibition. Therefore, when the temperature decreased, the inhibition ability of phIF to promoter PphIF was weakened or even lost, and MazF expressed a large number of toxic proteins, resulting in the death of E. coli. (MazF and MazE belong to the toxin-antitoxin suicide system.)

However, when the temperature increased to 37℃, CI857 repressor protein denaturated, CI repressor could no longer bind to promoter PR and play a repressor role, and a large number of downstream phIF protein inhibited promoter PphIF. Therefore, the expression of toxin MazF in the pathway was inhibited, and the MazE antitoxin protein at the end of the gene route was expressed instead. Eventually the E. coli survived.

The skeleton of this genetic route comes from Wang, X., et al.[1]

Usage and Biology

The gene route is temperature-controlled and can be used as a safety guarantee so that the engineered bacteria can die when they leave the human body (the temperature drops) and survive in the human body (37℃). It can solve the problem of handling engineered bacteria after they are discharged from the human body, ensuring that they play a role in the human body while doing not damage the environment. This part interplayed with part BBa_K4656013 to make up our yogurt-customized kill-switch circuit. Detailed information about our yogurt-customized kill-switch circuit can be found on our part BBa_K4656013.

Reference

[1] Wang, X., Han, J. N., Zhang, X., Ma, Y. Y., Lin, Y., Wang, H., Li, D. J., Zheng, T. R., Wu, F. Q., Ye, J. W., & Chen, G. Q. (2021). Reversible thermal regulation for bifunctional dynamic control of gene expression in Escherichia coli. Nature communications, 12(1), 1411. https://doi.org/10.1038/s41467-021-21654-x

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  INCOMPATIBLE WITH RFC[21]

  Illegal BamHI site found at 1625
  
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]