Tune in (to Wnt), turn on (gene expression), drop out (at intermediate frequencies)

Summary by Katherine Rogers: Rosen, S.J., Witteveen, O., Baxter, N., Lach, R.S., Hopkins, E., Bauer, M., and Wilson, M.Z. (2026). Anti-resonance in developmental signaling regulates cell fate decisions. Elife 14. 10.7554/eLife.107794.

Image Credit: Sardinia Radio Telescope by Mike Peel, Wikimedia Commons

Cell fate decisions are controlled by signaling molecules including Wnt. Recent work shows that signaling dynamics play an important role in regulating gene expression and cell fate decisions [1]. However, understanding the “rules” underlying interpretation of these dynamics is hampered by difficulties experimentally manipulating signaling and quantifying responses. Using elegant human cell culture systems that provide experimental control over Wnt signaling, together with readouts of signaling and gene expression, Rosen et al. 2026 reveals a surprising response to Wnt dynamics: Cells respond to both low and high Wnt signaling frequencies, but show dampened responses to intermediate frequencies [2].

To precisely control Wnt signaling and monitor responses, the authors generated “Wnt input/output” or “Wnt I/O” human cell lines. The cells express “Opto-Wnt”, an optogenetic tool that can reversibly activate Wnt signaling with blue light exposure. They also engineered a live readout of Wnt signaling by fluorescently tagging the Wnt effector beta-catenin, and added a live readout of Wnt-activated gene expression based on the “TopFlash” reporter assay [3] where Wnt-responsive elements drive fluorescent protein expression.

The authors first exposed the Wnt I/O line to light for six different durations (6-24 hours) and measured beta-catenin and TopFlash dynamics over 26 hours. Individual cell responses were variable, but at the population level, Wnt signaling duration correlated with both the maximum amplitude of beta-catenin, and TopFlash amplitude at 26 hours.

To assess how signaling dynamics influence Wnt interpretation, the authors subjected the Wnt I/O line to different light exposure dynamics over 48 hours to modulate two parameters: Duty cycle and frequency. Duty cycle refers to the total amount of time light is on—for example, 25% duty cycle means that cells are exposed to light for 25% of the 48 hours (12 hours). Frequency describes how that exposure is spread out over time—for example, all at once at the beginning (1/48 cycles/hour), or in 384 pulses spread out over the 48 hours (8 cycles/hour).

The Wnt I/O line was exposed to 96 different combinations: Eight duty cycles between 25-95%, and twelve frequencies from 1 cycle every 24 hours to 8 cycles/hour. At the end of 48 hours, at both high and low frequencies, TopFlash gene expression reporter was activated across all duty cycles. Strikingly, however, at intermediate frequencies and low duty cycles, TopFlash reporter levels were much lower. This behavior is consistent with the engineering concept of “anti-resonance”, where specific input frequencies produce minimal outputs.

The authors also developed a differential equation-based model of Wnt signaling and responses that accurately reflects real-world observations. Future studies could experimentally test the model’s predictions to directly determine the mechanisms underpinning anti-resonance. It could also be interesting to examine whether cell cycle differences explain the high cell-to-cell variability observed in Wnt responses in this study (a factor that influences responses to other pathways including FGF [4]). Finally, future studies could explore the biological roles of anti-resonance, which has been suggested to enhance developmental robustness by filtering noise, or even protect against cancer by allowing cells to “ignore” aberrant oncogenic signaling dynamics.   

References

1. Bosman, S.L., and Sonnen, K.F. (2022). Signaling oscillations in embryonic development. Curr Top Dev Biol 149, 341-372. 10.1016/bs.ctdb.2022.02.011.

2. Rosen, S.J., Witteveen, O., Baxter, N., Lach, R.S., Hopkins, E., Bauer, M., and Wilson, M.Z. (2026). Anti-resonance in developmental signaling regulates cell fate decisions. Elife 14. 10.7554/eLife.107794.

3. Korinek, V., Barker, N., Morin, P.J., van Wichen, D., de Weger, R., Kinzler, K.W., Vogelstein, B., and Clevers, H. (1997). Constitutive transcriptional activation by a beta-catenin-Tcf complex in APC-/- colon carcinoma. Science 275, 1784-1787. 10.1126/science.275.5307.1784.

4. Wilcockson, S.G., Guglielmi, L., Araguas Rodriguez, P., Amoyel, M., and Hill, C.S. (2023). An improved Erk biosensor detects oscillatory Erk dynamics driven by mitotic erasure during early development. Dev Cell 58, 2802-2818 e2805. 10.1016/j.devcel.2023.08.021.