Webb Group: How TLWD proteins form the spindle at the centre of circadian clocks.
Supervisor
Professor Alex Webb
Overview
Circadian clocks regulate nearly all aspects of plant biology. We have identified a new part of the circadian clocks. WD40 scaffold proteins of the TLWD family, interact with the transcription factors that form the clock. We want to understand this new dimension to circadian timing.
Project Summary
Circadian clocks are internal 24 hour timing devices. Eukaryotic circadian clocks comprise loops of expression of transcription factors which regulate each other to set up circadian timing, and regulate output genes to regulate cellular biology. Core to this hypothesis for circadian timing is the sequential presence and absence of these transcription factor proteins at different times of the day. We have identified a new class of proteins that are always present but are essential for circadian rhythms. These are WD40 proteins (TTG1, LWD1, LWD2) forming the TLWD family of scaffold proteins present in all Eukaryotes. TLWD proteins form complexes with transcription factors and are essential to regulate gene expression. We have mapped the amino acids within TLWD and circadian clock proteins that mediate interactions. We now wish to investigate the effect of interaction mutants on circadian rhythms in plants and understand why the TLWD proteins are essential arbors, or spindles, at the heart of the circadian oscillators of Eukaryotes. This project investigates a new aspect of circadian biology.
What will the successful applicant do?
The applicant will investigate how changing the interactions between the TLWD proteins and circadian oscillator proteins affect the circadian biology of the plant. Addtionally you will perform CHIPseq and molecular biology analysis to determine if interactions between TLWD and circadian oscillator proteins affect binding to DNA, transcriptional activity, or both.
References
Herrero, E., Cano-Ramirez, D., Glover, B.J. and Webb, A.A.R. (2025) Arbor function of TTG1 and LWD scaffold proteins in the Arabidopsis circadian oscillators includes transcriptional repression through PRR proteins. bioRxiv. DOI: 10.1101/2025.02.04.636234
Airoldi, C.A. Hearn, T.J., Brockington, S.F., Webb, A.A.R. and Glover, B.J. (2019) The evolution of the TTG1 protein family: from a central role in circadian clock to epidermal cell specification and pigment production. Nature Plants 5, 1145–1153. DOI: 10.1038/s41477-019-0544-3