This movie is a time-lapse series of phase contrast and fluorescence images (frame was taken every three minutes) of yeast growing on agarose pads under a fluorescence microscope. For a sense of scale, the yeast are typically several microns in diameter and divide approximately every 90 minutes. The yellow fluorescence is generated by yellow fluorescent protein (YFP), which is produced and controlled by a synthetic gene circuit built in the Buchler lab at [ Ссылка ].
This yeast contains a positive feedback genetic circuit (artificial trans-activator that binds its own promoter and increases its own gene expression). For the right parameters, these circuits can be bistable (i.e. stable, heritable OFF state and stable, heritable ON state, with noise-induced switching from OFF to ON and ON to OFF). YFP is fused to the trans-activator, so you can see the expression of the trans-activator. This work is unpublished, but it makes for a nice movie. This circuit is a variation of the synthetic circuit by Becskei et al, EMBO Journal (2001); see [ Ссылка ].
