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bioRxiv · 10.1101/2023.03.15.532793

Molecular basis of polyglutamine-modulated ELF3 phase change in Arabidopsis temperature response

Lindsay, R. J.·Wigge, P. A.·Hanson, S. M.
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Abstract

The evening complex (EC) is a tripartite DNA repressor and a core component of the circadian clock that provides a mechanism for temperature-responsive growth and development of many plants. ELF3, a component of the EC, is a disordered scaffolding protein that blocks transcription of growth genes at low temperature. At increased temperature EC DNA binding is disrupted and ELF3 is sequestered in a reversible nuclear condensate, allowing transcription and growth to proceed. The condensation is driven by a low complexity prion-like domain (PrD), and the sensitivity of the temperature response is modulated by the length of a variable polyQ tract, with a longer polyQ tract corresponding to enhanced condensate formation and hypocotyl growth at increased temperature. Here, a series of computational studies provides evidence that polyQ tracts promote formation of temperature-sensitive helices in flanking residues with potential impacts for EC stability under increasing temperature. REST2 simulations uncover a heat-induced population of condensation-prone conformations that results from the exposure of sticky aromatic residues by temperature-responsive breaking of long-range contacts. Coarse-grained Martini simulations reveal both polyQ tract length and sequence context modulate the temperature dependence of cluster formation. Understanding the molecular mechanism underlying the ELF3-PrD temperature response in plants has implications for technologies including modular temperature-response elements for heat-responsive protein design and agricultural advances to enable optimization of crop yields and allow plants to thrive in increasingly inhospitable environments.

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Lindsay, R. J., Wigge, P. A., Hanson, S. M.. 2023-03-16. Molecular basis of polyglutamine-modulated ELF3 phase change in Arabidopsis temperature response. https://doi.org/10.1101/2023.03.15.532793

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