Porin Gene Transcription in Single Cells
Transcription of GFP enables us to see how expression levels change in response to osmolality
In order to understand how the increased phosphorylation of EnvZ causes increased expression of OmpF and OmpC, we are analyzing ompF- or ompC- promoter fusions to the green fluorescent protein gene in single cells. The transcription of GFP from the fusions will enable us to see how expression levels change in response to osmolality. Our results indicate that the noise is intrinsic to the promoters and not dependent on copy number or location. Identical measurements in an flhDC null strain identify the master flagellar regulator FlhDC as an indirect regulator of ompC. This connection between FlhDC and the EnvZ/OmpR system has been noted by others studying mouse models of infection (Leatham et al., 2005, De Paepe et al., 2011). We are working to further understand this connection.
MG1655 cells that contain an ompC-gfp promoter fusion exhibit varying degrees of fluorescence in response to osmotic stress. Cells were grown overnight in LB and then sub-cultured in A media + 400 mM NaCl. The cells were placed on agar pads and their fluorescence was monitored over time in a Deltavision deconvolution microscope.
Researcher: Dr Yunfeng Gao
Lab: Linda J Kenney Lab
