Live-cell analysis of IMPDH protein levels during yeast colony growth provides insights into the regulation of GTP synthesis

Here we present real-time, live-cell analysis of accumulation of the Imd2 isoform of IMPDH in Saccharomyces cervisiae yeast cells forming a monolayer colony in a microfluidic device over a 50-hour time course. We observe two distinct phases of increased Imd2 accumulation: a guanine-insensitive phase early in outgrowth and a guanine-sensitive phase later, when cells become crowded. We show that the IMPDH inhibitor mycophenolic acid enhances both phases of increase. Deletion of a transcription attenuator upstream of the mRNA start site that decreases Imd2 mRNA synthesis in the presence of high GTP increases the baseline level of Imd2 protein ten-fold and abolishes guanine-sensitive but not guanine-insensitive induction. Our results suggest that at least two mechanisms of yeast Imd2 regulation exist, the known GTP-dependent attenuation of RNA polymerase II elongation and a GTP concentration-independent pathway that may be controlled by cell growth state., Refer associated mBio paper., , # Data from: Live-cell analysis of IMPDH protein levels during yeast colony growth provides insights into the regulation of GTP synthesis

[https://doi.org/10.5061/dryad.80gb5mkzb](https://doi.org/10.5061/dryad.80gb5mkzb)

The microscopy data underlying each data figure in the manuscript is contained in a single folder, corresponding to a single time course experiment on a 4-channel CellASIC plate. Each folder includes a metadata spreadsheet, a subfolder containing 3-4 raw microscopy (nd2) files, a subfolder containing ~100 merged tiff files (an exposure every 30 minutes over 50 hours) corresponding to each of the four experimental channels (xy1-xy4) and three different light sources (DIC, GFP, or mCherry, either individually or merged), and a \"cellMeasurements\" spreadsheet containing the results of analysis of the GFP fluorescence from each identified cell in the frame.

## Description of the data and file structure

Cells were identified and their GFP fluorescence measured from multic...