Difference between revisions of "Part:BBa K566042"

Latest revision as of 03:23, 29 September 2011

composite Biphasic switch

Biphasic switch (BBa_K566002) proof concept. Composite part of BBa_K566015, BBa_K145015, BBa_B0014 and BBa_K566039

Usage and Biology

The biphasic switch may be used to control both expression and repression of pRM through a single input, which must control cI protein concentration. Furthermore, if repressor cI434 is placed under pRM's control along with the gene of interest, this switch may be coupled with the modified promoter pRM434 (BBa_I12006), which is stimulated by cI but repressed by cI434; hence resulting in a two-state switch controlled through a single input. The expected behavior will be the following: 1) at low concentrations of cI, both promoters will be activated. However, because of cI434 repressing pRM434, only pRM will stay ON eventually leading to the first state. 2) At high concentrations of cI, pRM -and consequently cI434- will be turned OFF, allowing pRM434 to be activated by cI and leading to a second state. pRM promoter from Phage 434 (not to confuse with pRM434 mentioned above) seems to exhibit the same biphasic behavior (4). This part is intended to prove the behavior shown in figure 1, using fluorescent proteins as reporter genes. It is coupled with the part K566040 , which contains the pRM434 promoter. GFP -transcribed from pRM- represents the first state, while YFP -transcribed from pRM434- represents the second state.

Figure 1. Expected behavior of biphasic switch coupled with pRM434. GFP and cI434 are placed under the control of pRM. At low concentrations of cI, GFP's and cI434's expression are stimulated. At high concentrations of cI, GFP and cI434 get repressed, allowing the expression of YFP. cI is transcribed from the pTetMnt promoter, and can therefore be regulated through two repressors. The data used for this graph is not real, for explanation purposes only.

Sequence and Features