The Cambridge Companion to English Renaissance Drama
The two models shown in Fig. 5 are slight variations of a model proposed and discussed previously (Hong et al. 2008) . We here summarize the components of the models and their rate equations. Steps 1-6 represent the expression of frq, including transcription (step 1), translation (step 2) and translocation of FRQ protein into the nucleus (step 3), the degradation of frq mRNA (step 4), as well as degradation of cytosolic and nuclear FRQ (steps 5-6). Because there is much less nuclear FRQ than
... nuclear FRQ than cytoplasmic FRQ, and because the degradation rate constant of nuclear FRQ (k 6 ) is significantly lower than the cytosolic FRQ degradation rate constant (k 5 ), in the model the degradation of total FRQ is mostly determined by the cytosolic FRQ degradation. The cytosolic FRQ degradation rate constants are in good agreement with experimental estimates of total FRQ degradation (Table 1, Ref. 29). The results from the model remain similar even when k 5 and k 6 values are set equal to the experimental FRQ degradation rate constants but with slightly shorter periods and reduced amounts of FRQ. Steps 7-12 represent the expression of wc-1 and nuclear localization of WC-1 with degradation reactions (steps 10-12). WC-2 is present in excess over WC-1 and the concentration of WC-2 does not change during the circadian cycle (Cheng et al. 2001; Denault et al. 2001) . Therefore, we consider WC-2 as a constant and have not included WC-2 in the model. In addition, the WCC complex is represented by WC-1 n . Step 8 describes the FRQ promoted accumulation of WC-1. The step with rate constant k 02 represents a minor contribution to WC-1 c synthesis in the absence of FRQ (Lee et al. 2000; Cheng et al. 2001; Schafmeier et al. 2006) . Steps 13-15 represent the inactivation of WC-1 n by binding to FRQ n with a 1:1 stoichiometry.