# In vivo tracking of bioluminescent markers of circadian rhythms in behaving animals

> **NIH NIH R15** · SMITH COLLEGE · 2024 · $37,099

## Abstract

Project Summary
Circadian rhythms are fundamental in sculpting physiology, and their alignment is essential for
optimal health. We have gained deep understanding of the cellular basis as well as the function of the
central circadian clock of the suprachiasmatic nuclei (SCN), but we don’t yet understand how the
SCN interacts with varied peripheral oscillators, and how these peripheral clocks integrate information
from SCN- and non-SCN-inputs to maintain internal alignment as well as entrainment to 24h cycles.
Here we will study two peripheral oscillators, the liver and skin. We will develop an animal model for
study of the role of these peripheral clocks within the circadian system, to determine their entrainment
capabilities.
The central hypothesis of this proposal is that peripheral clocks retain some rhythmic
capabilities when the SCN central clock is impaired, possibly including photic entrainment. The long term
goal of this research is to understand the inter-dynamics of circadian clocks throughout the
mammalian body and, ultimately, discover new tools to lessen the impact of circadian misalignment
on health.
Our research will first aim to characterize our new skin circadian clock reporter line K14 Cre;
DBPKI/+ mice. We will more fully characterize our new mouse line using IVIS imaging, assays, and
histology to rigorously determine sources of the bioluminescence recorded. Second, we will aim to
test photic entrainment of skin and liver circadian rhythms in vivo in mice with or without brain central
clock function. This aim will test the entrainment of skin and liver using methods for long-term
circadian bioluminescent reporting from living animals, first in intact mice and then in mice with
suprachiasmatic nuclei (SCN) ablation. Third, we will determine if these peripheral tissues show a
wider range of entrainment than the central clock. We will test the ability for circadian rhythms of gene
expression of K14 Cre; DBPKI/+ and Alb Cre; DBPKI/+ mice to entrain to cycles of varied cycle lengths
(“T cycles”), to assess the range of entrainment, as compared with that of locomotor activity, using both
intact and SCN-lesion mice.
Completion of these studies will dramatically alter our understanding of the mammalian
circadian system to include potentially photoreceptive peripheral clocks. The research will be
conducted by diverse and engaged undergraduate women, with structured mentoring to encourage
continued careers in biomedical science.

## Key facts

- **NIH application ID:** 11043849
- **Project number:** 3R15GM126545-03S1
- **Recipient organization:** SMITH COLLEGE
- **Principal Investigator:** MARY E HARRINGTON
- **Activity code:** R15 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $37,099
- **Award type:** 3
- **Project period:** 2017-09-15 → 2026-09-17

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11043849

## Citation

> US National Institutes of Health, RePORTER application 11043849, In vivo tracking of bioluminescent markers of circadian rhythms in behaving animals (3R15GM126545-03S1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/11043849. Licensed CC0.

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