| Description |
Genes can be switched on or off by regulatory proteins. For example, two genes may each synthesize a protein that downregulates the other gene, creating a repressor- repressor switch that has two stable steady states: one being when the first gene is "on" and the second gene is repressed, and the other in which the situation is reversed. Previous study of a model by Cherry and Adler showed that the existence of such a switch depends on factors including the shapes of the two repression functions. Adding to the model an additional point of control mRNA dynamics-resulted in further restrictions upon the parameters that can lead to a functional genetic switch. Specifically, compared to the original model, it is twice as difficult for a system that takes into account second-order mRNA decay to have a working switch, and three times as difficult for a system that takes into account third-order mRNA decay. |
