# Role of microtubules in the non-cell autonomous activities of plant microRNAs

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA RIVERSIDE · 2020 · $311,000

## Abstract

PROJECT SUMMARY
microRNAs (miRNAs) are sequence-specific regulators of gene expression that impact almost all biological
processes in diverse eukaryotes. Defects in miRNA-based regulation lead to developmental and physiological
abnormalities in both plants and animals. Thanks to nearly two decades of research, the molecular machinery
responsible for miRNA biogenesis and modes of action has been uncovered. However, since most biochemical
studies on miRNAs or related small interfering RNAs were performed with cell-free extracts, how the small
RNA machinery interplays with the cytoskeleton remains largely unknown. Historically, miRNAs are viewed as
cell-autonomous regulatory molecules, but in recent years, mounting evidence points to the existence of
miRNAs in extracellular vesicles in animals as well as the movement of miRNAs between cells in plants.
Despite accumulating evidence implicating miRNAs as informational molecules in cell-cell communications, the
scope of biologically significant, non-cell autonomous activities of miRNAs is largely unknown, let alone the
molecular mechanisms that enable, constrain, or regulate the non-cell autonomy of miRNAs.
 The project interrogates the scope of miRNAs serving as informational molecules in cell-cell
communications and investigates the mechanisms underlying the non-cell autonomous activities of miRNAs
using the Arabidopsis model. In addition to sophisticated tool sets as available resources, advantages offered
by the Arabidopsis model include the well-documented, non-cell autonomous activities of a few miRNAs in
intact plants and the ease to perform forward genetic screens that do not require any a priori assumptions
regarding the cellular machinery for miRNA’s non-cell autonomy. A forward genetic screen from the PI’s group
revealed a previously unsuspected link between microtubules and the non-cell autonomous activities of
miRNAs as well as a tantalizing connection between the translation repression activities of miRNAs and their
non-cell autonomous activities. The project takes advantage of the layered cell organization in roots and
employs genomics approaches at single-cell-layer resolution to study how microtubules enable the non-cell
autonomous activities of miRNAs.
 By elucidating the scope of miRNA’s non-cell autonomy, the project has the potential to change the
dogma that miRNAs largely act cell-autonomously and set the paradigm that miRNAs serve as signals in cell-
cell communications. Through pioneering efforts to interrogate mechanisms underlying the non-cell
autonomous activities of miRNAs, the project will provide initial knowledge in this largely unknown territory and
set the foundation for future studies. By revealing a role of the cytoskeleton in small RNA biology, the impacts
of the project will reach beyond plant biology.

## Key facts

- **NIH application ID:** 9996724
- **Project number:** 5R01GM129373-03
- **Recipient organization:** UNIVERSITY OF CALIFORNIA RIVERSIDE
- **Principal Investigator:** Xuemei Chen
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $311,000
- **Award type:** 5
- **Project period:** 2018-09-05 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9996724

## Citation

> US National Institutes of Health, RePORTER application 9996724, Role of microtubules in the non-cell autonomous activities of plant microRNAs (5R01GM129373-03). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9996724. Licensed CC0.

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