 |
I am fascinated by a fundamental question in biology; How is regulation of gene expression as a response to external stimulus achieved? Expression of approximately seventy genes in E. coli are affected by increasing osmolality of growth medium. A current model of osmoregulation in E. coli suggests that the cell strives to maintain the pressure exerted by the cytoplasmic membrane on the cell wall (turgor) at some fixed set point. Upon osmotic upshock, potassium, glutamate and trehalose concentrations in the cytoplasm all increase dramatically and putrescine levels decrease. The changes in solute composition result from a complex network of gene expression which is carefully regulated. At least two signals appear to be important in initiating changes in gene expression which help maintain turgor; turgor pressure itself and cytoplasmic K+ activity. These signals are sensed and relayed to regulator factors which influence the transcription and the translation of genes which are involved in synthesizing or transporting cytoplasmic solutes.
|
|
 |
Schlax, Paula J.
Associate Professor
207-786-6290
Dana Chemistry Hall, Room 220
pschlax@bates.edu
|
|
|
