Anderson Promoter Characterization
The Anderson promoters are a collection of variable strength constitutive promoters for use in E. coli
and other prokaryotes. They were created from a consensus sequence (J23119) by Chris Anderson. The table below lists, for the promoters we characterized, their relative strengths and the sequence changes (in red) that distinguish each promoter from the consensus.
The relative strengths of these promoters were measured by Chris Anderson and the 2006 Berkeley iGEM team. These measurements are explained in greater detail in the Characterization section below. Source: http://parts.igem.org/Promoters/Catalog/Anderson
In order to further characterize these promoters, we created several transcriptional units containing different Anderson promoters and a gene for GFP. After transforming into E. coli
, we measured fluorescence on a flow cytometer. The results, after gating out anything except bacteria, are below.
* Duplicate prepared using alternate protocol
The controls functioned as expected: untransformed E. coli
exhibited essentially no fluorescence and the beads, while having a high fluorescence initially, were removed by the gating for debris (anything other than bacteria).
Oddly, the construct with J23100, which should have been the strongest of the promoters, also did not fluoresce. Though we are unsure of the reason, it may have been human error such as a mislabeling of a tube. Also unexpected was the low, though discernable, level of fluorescence with J23107 which was six times lower than measured by the Berkeley 2006 team (by comparison between J23107 and J23102). J23116 showed expression around the same levels as the Berkeley team demonstrated.
Because J23102 exhibited the highest level of fluorescence, it was the promoter which we used throughout our experiments this summer in all of the transcriptional units which we made.