Team:Groningen/Promoters draft


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An important question is which promoter we should use to control the chaplin expression. We assume that an ideal promoter would not be active until the biofilm has formed because the expression of hydrophobic proteins might influence the formation of it. Two promoters where found that are active in biofilms but not during normal growth.

srfA promotor activity during cell growth


The srfA operon has been reported to be important for natural competence and sporulation in Bacillus Subtilis. All these activities occur in biofilms, the promoter is not active until the end of exponential growth. It is controlled by the ComXPA quorum sensing system and hence active in states of high cell densities. Therefore the srfA promoter would be suitable for chaplin expression. Two different lengths of the srfA promoter where chosen due to uncertainties concerning the region between the response element ant the transcription start side of the srfAA protein. In the original promoter this region is unusually long, by shortening it 190bp’s we hope to achieve a higher transcription efficiency. So we came up with two different promoters, the original one and the shortened one.


yqxM promotor activity during cell growth of different mutants

The yqxM-sipW-tasA operon is controlled by the yqxM promoter. It is needed for biofilm formation because tasA is a key protein of the extracellular matrix. The promotor gets activated via a cascade of other regulatory elements in response to quorum sensing Since the caplins should work in a similar way to tasA we think the yqxM promoter would be very suitable for chaplin expression during the stationary phase.

Quorum sensing and promoter interactions



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