Difference between revisions of "Part:BBa M45113"

Latest revision as of 08:11, 17 April 2014

Uranium Inducible (urcA) Promoter

The promoter was designated urcA for uranium response in the bacterium Caulobacter. It is activated in the presence of the uranyl cation, a soluble form of uranium (Hillson et al., 2007).

The uranyl ion (UO2,2+ ) is the most water-soluble and bioavailable form of uranium and poses the greatest threat to human health. Due to the ease of uranyl ion spread through groundwater systems, most bioremediation strategies attempt to prevent contaminating uranium spread by utilizing microorganisms to reduce the oxidation state of uranium from U(VI), found in uranyl, to less soluble forms of uranium, including U(IV)(Hillson et al., 2007).

The urcA promoter is specific for uranium and has little cross specificity for nitrate (<400 M), lead (<150 M), cadmium (<48 M), or chromium (<41.6 M). It was induced 27.5-fold under uranium stress, but was not upregulated in response to other heavy metals in the test screen. For this reason, the urcA promoter was selected as a candidate to drive uranium reporter constructs(Hillson et al., 2007).

Usually promoters from Caulobacter species will include at least one uranium-specific m_5 motif sequence. The urcA promoter contains two matches to this motif, located 107 and 55 bp upstream of the putative +1 site (Hillson et al., 2007).

Reference:

Nathan J. Hillson, Ping Hu, Gary L. Andersen and Lucy Shapiro. Caulobacter crescentus as a Whole-Cell Uranium Biosensor. Appl. Environ. Microbiol. 2007, 73(23):7615. DOI: 10.1128/AEM.01566-07. Retrieved from: file:///C:/Users/Owner/Desktop/Appl.%20Environ.%20Microbiol.-2007-Hillson-7615-21.pdf

Sequence and Features