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  • The timing of Start is determined primarily by increased synthesis of the Cln3 activator rather than dilution of the Whi5 inhibitor
Title: The timing of Start is determined primarily by increased synthesis of the Cln3 activator rather than dilution of the Whi5 inhibitor
In their Letter to Molecular Biology of the Cell, Schmoller et al. (2022) raise questions about the results and conclusions presented in our published studies (Dorsey et al., 2018; Litsios et al., 2019). Here, we respond to the criticisms of Schmoller et al. and demonstrate how wide-field fluorescence microscopy experiments to determine nuclear Whi5 concentration dynamics can be confounded by uncontrolled effects, which include photobleaching, partial confocal effects, and nuclear-to-cytoplasmic volume scaling. Further, we provide additional experimental evidence demonstrating that nuclear Whi5 concentration is essentially constant as cells grow in G1 phase and that Cln3 and protein synthesis dynamics occur as reported in Litsios et al. (2019). These results suggest that instead of being triggered by dilution of the stable inhibitor Whi5, Start is rather primarily controlled by the increase in protein synthesis rate in G1 and the concomitant production of the unstable activator Cln3.  more » « less
Award ID(s):
1806638
PAR ID:
10338168
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ;
Editor(s):
Sophie Martin
Date Published:
Journal Name:
Molecular biology of the cell
Volume:
33
ISSN:
1059-1524
Page Range / eLocation ID:
1-14
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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