Part:BBa_K342000

Curli Promoter induced by temperature, shaking speed and osmolarity,

Properties of the part

Promoter induced by temperature, shaking speed and osmolarity.

Characterization (New data, 2014)

This promoter (P70) is a shorter and simplified version of the full curli intergenic region (P750). We compared the expression of the two constructs. The shorter promoter K342000 has the interesting property of being expressed both at 30°C and 37°C, on the contrary to the natural 750 base-pair CsgA promoter from where it is orginially isolated which is expressed only at 30°C.

On a pKK backbone, two essential parts have been assembled: a promoter and a reporter. The reporter in this case is always the same: GFP. However, the promoter is different for each construction. On the one hand, P70 is the 70 base-pair long promoter sequence and when combined to the reporter GFP is called p70:GFP. On a second hand, P750 is the 750 base-pair long promoter sequence coding for the inter-genic regulation for curli production and combined to the reporter GFP is called P750:GFP.
The construction used to characterize this part is shown in the figure below. The fluorescence data obtained was converted to transcription rates using the model presented in De Jong 2010.

Early growth stage promoter kinetics
During the early growth stages at 37°C, we can observe that the P70 (orange) has a higher transcription level compared to P750 (red). However at 30°C, both P70 (light blue) and P750 (dark blue) have low transcription levels. We conclude that P70 (K342000) has the ability to prematurely activate downstream expression at 37°C

Late growth stage promoter kinetics
During the late growth stages at 37°C, we can observe that both P70 (orange) and P750 (red) have a decreasing transcription rate. However at 30°C, P70 (light blue) stabilizes at a low transcriptional level and P750 (dark blue) reaches the highest transcriptional levels. We conclude that P750 has a delayed, albeit extremely strong, transcription rate at 30°C compared to P70.

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]