Part:BBa_K2969021

TCI

TCI is a temperature-sensitive variant of the bacteriophage λ repressor cI. It consists of N-terminal, C-terminal and the fragment between N-terminal and C-terminal whose function is the linkage. It is a cold-inducible transcription factor. When the temperature is below 35℃, the activity of TCI will gradually rising. When the temperature is above 35℃, the activity of TCI will remain at a low level.

Characterization

In 2019, UCAS-China developed a collection of thermosensitive parts with high-performance, versatility and robustness. Based on TCI transcription factor family and TlpA family, we collected five TCI and TlpA mutants and used sfGFP as reporter to build some heat-inducible ON-switches, which can open gene expression under high temperature. To characterize them quantitatively, we first characterized the performance of them by flow cytometer in Top10 strain.

As shown in Figure 1, most of the transcription repressors show sharp thermal transitions, especially TCI and TCI42, with more than 100-fold induction within 10 degrees Celsius. Their impressive performances make them candidate parts for our further circuit design.

Figure 1:The induction curves of the heat-inducible switches (TOP10)

What’s more, we also tested these heat-inducible ON-switch in the chassis E.coli Nissle 1917, a probiotic with more than 100 years of medical application, their robustness give us more confidence in the stability and preciseness of our ark. The result is shown in Figure 2.

Figure 2:The induction curves of the heat-inducible switches (Nissle 1917)

Reference

Piraner, D. I., Abedi, M. H., Moser, B. A., Lee-Gosselin, A., and Shapiro, M. G., Tunable thermal bioswitch for in vivo control of microbial therapeutics. DOI: 10.1038/NCHEMBIO.2233

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]