RT Journal Article
SR Electronic
T1 Constitutive expression of a fluorescent protein reports the size of live human cells
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 587162
DO 10.1101/587162
A1 Daniel F. Berenson
A1 Evgeny Zatulovskiy
A1 Shicong Xie
A1 Jan M. Skotheim
YR 2019
UL http://biorxiv.org/content/early/2019/03/23/587162.abstract
AB Cell size is intimately related to cell physiology because it sets the geometric scale of organelles and biosynthesis. A number of methods exist to measure different aspects of size of individual cells, but each has significant drawbacks. Here, we present an alternative method to measure the size of single human cells using a nuclear localized fluorescent protein expressed from a constitutive promoter. We validate this method by comparing it to several established cell size measurement strategies, including flow cytometry optical scatter, total protein dyes, and quantitative phase microscopy. We directly compare our fluorescent protein measurement to the commonly used measurement of nuclear volume and show that our measurements are more robust and less dependent on image segmentation. We apply our method to examine how cell size impacts the cell division cycle, which reaffirms the importance of G1/S size control. Importantly, combining our size reporter with fluorescent labeling of a different protein in a different color channel allows measurement of concentration dynamics using simple widefield fluorescence imaging. Thus, we expect our method will be of use to other researchers interested in the topics of cell size control and, more broadly, how dynamically changing protein concentrations control cell fates.