The Novak–Tyson Model is a non-linear dynamics framework developed in the context of cell-cycle control by Bela Novak and John J. Tyson.
[1] In 1990, two key papers were published that identified and characterized important dynamic relationships between cyclin and MPF in interphase-arrested frog egg extracts.
[5] When graphing the MPF activity with respect to cyclin concentration, the model shows a sigmoidal shape, with a hypersensitive, threshold region similar to what was observed by Solomon.
[1] The model proposes a complex set of feedback relationships that are mathematically defined by a series of rate constants and ordinary differential equations.
It employs concepts seen in the previous models such as stoichiometric binding of Cdc2 and cyclin B, positive feedback loops through Cdc25 and Wee1, and delayed activation by MPF of the APC, but includes additional reactions such as that of Wee1 and Cdc25.
[1] Novak and Tyson predict that unreplicated DNA interferes with M-phase initiation by activating the phosphatases that oppose MPF in the positive feedback loops.
[7] At the time of publishing, the predictions from the paper were all experimentally untested and were based only off the signal pathways and mathematical modeling proposed by Novak and Tyson.