Revision as of 07:19, 17 October 2018

P_asr-B0034-sfGFP

Background

The asr promoter was first described by Suziedeliene et al. in 1999. They showed that asr is induced under low pH which is about pH 4.8, and it is controlled by the phoBR system. From the article they have published, the promoter is named as acid shock RNA (asr) promoter due to the RNA that has been transcribed after putting the E. coli into a low pH condition.

In 2007 Ogasawara et al2. found out that there is another regulatory system that controlling asr transcription by using SELEX to find the binding sequences of PhoQP-RstBA. Hence the asr promoter is directly controlled by two different systems, the phoBR system activated through low inorganic phosphate and the RstAB system sensing the pH while it is controlled by PhoQP-system activated by low Mg²⁺ concentrations.

Function of asr promoter in sfGFP reporting system

To expand the possible application of asr promoter, 2018 iGEM NCKU_Tainan put it together with sfGFP and tested this reporting system with more delicate pH gradings since a green fluorescent would be expressed once the promoter has been activated. In conclusion, we could monitor the pH in the surrounding medium in our device at any time by observing the color change of the medium.

Characterization

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Sequence and Features