Gene Descriptions

OmpR and p-OmpR

   OmpR is a transcriptional regulator native to E. coli. It is part of the EnvZ/OmpR two-component signal transduction system and is controlled by the kinase EnvZ. In wildtype E. coli, EnvZ upregulates OmpR in high osomlarity conditions, phosphorylating it to create p-OmpR.

OmpC and OmpF

   OmpC is an E. coli Promoter that is activated by the EnvZ/OmpR signal transduction system. In the presence of phosphorylated OmpR (called p-OmpR), transcription of OmpC is allowed and genes under the control of OmpC are expressed. In wildtype E. coli, when no p-OmpR is present within the cell, OmpR instead regulates the expression of the promoter OmpF.


   The sensory histidine kinase EnvZ is responsible for controlling the function of OmpR, which in turn upregulates either OmpC or OmpF. EnvZ undergoes autophosphorylation. In high osmolarity conditions, this phosphate group is passed to OmpR, generating p-OmpR. The mechanism by which EnvZ responds to osmolarity is unknown. EnvZ is located in the inner membrane of the cell, containing two transmembrane domains, a cytoplasmic domain, and a periplasmic domain.


   The RFP we use comes from the iGEM registry ( part BBa_E1010). It is native to the coral Discosoma striata. The exctitation wavelength of RFP is 584nm and it has an emission wavelength of 607nm.


Tar is an MCP (methyl-accepting chemotaxis protein) native to E. coli that responds primarily to aspartate. Tar contains two transmembrane domains, and a periplasmic ligand sensing domain, which recognizes the presence of aspartate via binding to this region.