# Function of photobodies in Arabidopsis photoreceptor signaling

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA RIVERSIDE · 2020 · $422,109

## Abstract

Abstract
How the cell nucleus is functionally and dynamically organized is a central question to understanding basic
cellular processes, including genome organization and transcriptional regulation. The interphase of both animal
and plant nuclei contain morphologically distinct, non-membrane bound subnuclear organelles that are
collectively called nuclear bodies. Although accumulating evidence suggests that nuclear bodies play important
roles in gene regulation, and changes in the morphology and constitution of nuclear bodies have been
associated with diseases, the precise function and regulatory mechanism of nuclear body biogenesis in
transcriptional regulation remain poorly understood. One major challenge has been the lack of genetic models
to delineate the functions of nuclear bodies in the context of transcriptional regulation by cell signaling. The
long-term goal of the PI’s laboratory is to utilize the photobody – a subnuclear domain in Arabidopsis
containing the photoreceptor phytochrome B (PHYB) – as a genetic model to elucidate the function of nuclear
bodies in cell signaling and transcriptional regulation. The current data support the central hypothesis that
photobodies are transcriptional regulatory foci wherein PHYB recruits transcription factors to regulate their
stability as well as the activity of their target genes. This hypothesis has been formulated on the basis of the
PI’s previous molecular genetic studies on two new light signaling components required for photobody
biogenesis, named HMR and RCB, and on the preliminary results showing direct recruitment of individual
genes to photobodies. Here the PI plans to test this central hypothesis by the following specific aims: (1)
Determine the function of photobodies in regulating the stability of transcription factors; (2) Determine the role
of RCB in the function and biogenesis of photobodies; (3) Determine the mechanism of spatial genome
organization by photobodies. The proposed research is innovative, because it utilizes the photobody and
photoreceptor signaling in Arabidopsis as a genetic model to investigate the enigmatic mechanisms of nuclear
organization – the function and biogenesis of nuclear bodies in transcriptional regulation and genome
organization. The PI’s laboratory pioneered the development of the photobody model, identified new signaling
components required for photobody formation by multiple forward genetic screens, and established a
mechanistic link between photobodies and transcriptional regulation. The proposed research is significant
because it is expected to uncover novel mechanisms linking nuclear body biogenesis to the regulation of the
stability of transcription factors as well as the activity of their target genes. Because the basic principles of
gene regulation are conserved across the animal, fungal, and plant kingdoms, a better understanding of the
function of photobodies in Arabidopsis will contribute to understanding of the evolutionarily conserved
p...

## Key facts

- **NIH application ID:** 10122729
- **Project number:** 2R01GM087388-11A1
- **Recipient organization:** UNIVERSITY OF CALIFORNIA RIVERSIDE
- **Principal Investigator:** Meng Chen
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $422,109
- **Award type:** 2
- **Project period:** 2010-09-01 → 2024-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10122729

## Citation

> US National Institutes of Health, RePORTER application 10122729, Function of photobodies in Arabidopsis photoreceptor signaling (2R01GM087388-11A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10122729. Licensed CC0.

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