# Inter- and intracellular mechanisms of circadian regulation

> **NIH NIH R35** · OHIO STATE UNIVERSITY · 2021 · $390,000

## Abstract

Project Summary
Circadian rhythms are nearly ubiquitous endogenous timing systems that help coordinate the myriad
physiological, metabolic and developmental processes that occur continuously in each organism at all times of
the day. This circadian clock is comprised at the molecular level of interlocked and autoregulatory feedback
loops that are built from complex interactions that are constantly changing in relation to each throughout the 24
hour cycle. The long term goal of this project is to understand the functional relationships among the inter- and
intracellular processes that keep the circadian oscillator running and coordinated across the plant. We are
using genetic, genomic, biochemical and cell biological tools and strategies of the model plant Arabidopsis to
identify the molecules and mechanisms that regulate the transport of clock proteins between the cytosol and
nucleus. We are focused in part on how post-translational modifications of clock proteins affect both their
positional and temporal intracellular localization. Gatekeeping features of the intracellular environment, such as
the nuclear pore (NP), are also addressed, using select NP mutants, and at the level of a single molecular
species. We are applying for the first time in circadian studies single cell imaging techniques using a
photoswitchable fluorescent protein to assess features of clock protein movement and turnover that will be
applicable to non-plant circadian systems. Long-distance circadian signaling from shoot to root will be explored
using select photoreceptor, kinase and glucose-signaling mutants as well as aberrant meristem mutants.
Unbiased mutant screens to identify proteolytic factors controlling clock protein levels will help understand the
importance of precise time-of-day phasing of these factors. We are also exploiting certain plant-specific
advantages of small RNA processing to address other post-transcriptional control mechanisms of the circadian
clock. Taken together our program will probe mechanisms of circadian control that should be broadly
applicable across all eukaryotic systems.

## Key facts

- **NIH application ID:** 10134379
- **Project number:** 5R35GM136400-02
- **Recipient organization:** OHIO STATE UNIVERSITY
- **Principal Investigator:** DAVID E SOMERS
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $390,000
- **Award type:** 5
- **Project period:** 2020-04-01 → 2025-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10134379

## Citation

> US National Institutes of Health, RePORTER application 10134379, Inter- and intracellular mechanisms of circadian regulation (5R35GM136400-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10134379. Licensed CC0.

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