Cell state transitions are often triggered by large changes in the concentrations of transcription factors and therefore large differences in their stoichiometric ratios. Whether cells can elicit transitions using modest changes in the ratios of co-expressed factors is unclear. Here, we investigate how cells in the Drosophila eye resolve state transitions by quantifying the expression dynamics of the ETS transcription factors Pnt and Yan. Eye progenitor cells maintain a relatively constant ratio of Pnt/Yan protein, despite expressing both proteins with pulsatile dynamics. A rapid and sustained twofold increase in the Pnt/Yan ratio accompanies transitions to photoreceptor fates. Genetic perturbations that modestly disrupt the Pnt/Yan ratio produce fate transition defects consistent with the hypothesis that transitions are normally driven by a twofold shift in the ratio. A biophysical model based on cooperative Yan-DNA binding coupled with non-cooperative Pnt- DNA binding illustrates how twofold ratio changes could generate ultrasensitive changes in target gene transcription to drive fate transitions. Thus, coupling cell state transitions to the Pnt/Yan ratio sensitizes the system to modest fold-changes, conferring robustness and ultrasensitivity to the developmental program. The data consist of several subdirectories of .silhouette files, each of which represents a single eye imaginal disc in which cell nuclei were segmented and manually annotated using the Silhouette app for MacOS. Subdirectory names denote the corresponding genetic condition, and all discs within a given directory are biological replicates. Each .silhouette file contains both the confocal images and all of the quantitiative data generated by the Silhouette app. A series of Jupyter notebooks that walk through the analysis of the included .silhouette files has been made available on GitHub ( https://github.com/sbernasek/pnt_yan_ratio).

Last modified

• 04/06/2023

Creator

• Carthew Lab
• Amaral Lab
• Rebay Lab

DOI

• https://doi.org/10.21985/n2-fkxb-x241

Publisher

• Northwestern University

Date created

• 04/06/23

Resource type

• Dataset

License

• Creative Commons CC0 1.0 Universal

Total Size

• 4.75 GB