Poster Presentation International Plant Molecular Biology Conference 2024

Identifying the regions necessary for the transcriptional regulatory activity of intrinsically disordered proteins LNK1 and COR27 in the Arabidopsis circadian clock (#177)

Stefanie F King 1 , Maria L Sorkin 2 , Dmitri A Nusinow 3
  1. Washington University in St. Louis, St. Louis, MO, United States
  2. Ginkgo Bioworks, Inc., Cambridge, MA, United States
  3. Donald Danforth Plant Science Center, St. Louis, MO, United States

Plants perceive time of day by sensing the changes in environmental light and temperature through their internal timekeeper, the circadian clock1,2. The plant clock functions through transcriptional-translational feedback loops where circadian proteins enact time-of-day-specific transcription regulation to generate biological rhythms1,3. The REVEILLE 8 (RVE8), NIGHT LIGHT-INDUCIBLE AND CLOCK REGULATED 1 (LNK1), and COLD REGULATED GENE 27 (COR27) complex is a critical light- and temperature-responsive junction within the plant clock2–9. In the afternoon, the RVE8-LNK1 complex activates transcription of evening-expressed clock genes3,4,8,9. While in the evening, these transcriptional targets are repressed when COR27 associates with RVE8-LNK1 and facilitates the degradation of RVE85–7. As intrinsically disordered proteins, LNK1 and COR27 lack well-folded protein structures and domains of known function5. Eukaryotic transcription factors often contain intrinsically disordered regions (IDRs) which allow the flexible, yet tight, control of transcriptional machinery10. The protein regions necessary for the transcription regulation mechanisms of LNK1 and COR27 are unknown5. I hypothesize that sequence motifs in LNK1 and COR27 IDRs are responsible for their transcriptional regulatory activity by enabling key protein-protein interactions. I use a combination of in silico sequence analyses and predictions paired with in planta assays to design and test LNK1 and COR27 internal deletion mutants for loss of transcriptional activation and repression activity. Preliminary results identified regions necessary for LNK1- and COR27-mediated transcription regulation. This work contributes to understanding how IDRs within transcription factors control transcriptional outputs in the plant circadian clock.

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