# Transcriptional regulatory mechanisms of vertebrate regeneration

> **NIH NIH R01** · UNIVERSITY OF WASHINGTON · 2021 · $334,201

## Abstract

Why do humans fail to regenerate injured central nervous system tissues, when other vertebrates do so
readily? In this proposal we take aim at this fundamental question by defining the cell-intrinsic mechanisms that
enable spinal cord regeneration in the frog Xenopus tropicalis. Tadpoles of this species are able to regenerate
spinal cord tissues and motor function following injury, while adult animals cannot. We will exploit this temporal
competence to regenerate in order to understand how regeneration normally proceeds as well as why it might
fail. This distinctive biology coupled with the deep set of available tools for functional and genomic analysis
makes X. tropicalis a uniquely powerful system for analysis of regeneration. A central goal of spinal cord
regeneration research is to identify the cell-intrinsic factors that enable neurogenesis and axon regeneration.
Our preliminary analyses in this system have uncovered new insights into these factors and the gene
regulatory mechanisms that may form the basis for regenerative competence. First, we have found that tens of
thousands of genomic regions shift rapidly to an accessible chromatin conformation, and then unexpectedly to
an inaccessible conformation, within the first few hours of regeneration. These rearrangements take place in
regions that are heavily enriched for binding sites of FoxO1 and Ascl1, factors that have pioneer activity and
critical roles in neural progenitor function. Second, genes specific to differentiated neurons are expressed
within hours of amputation, and are surprisingly independent of neural induction and neurogenesis gene
activation. Based on these observations, we hypothesize that regenerative competence relies on three
features: 1) a robust neural progenitor population, 2) a rapid burst of chromatin remodeling in neural progenitor
cells carried out by Ascl1, FoxO1, and other pioneer factors, and 3) activation of neuronal specific genes that
allow axonogenesis and neuronal growth in existing differentiated neurons. In this proposal, we will test these
predictions by identifying the transcription factors that mediate chromatin remodeling in isolated neural
progenitors. We will functionally test the role of Ascl1 and FoxO1 in regeneration using loss-of-function mutants
for these factors. We will then identify whether upregulation of axonogenesis genes in regenerating tadpoles
represents neuronal repair or neurogenesis, and interrogate whether these genes are upregulated using
embryonic gene regulatory elements or regeneration-specific regulatory elements. Finally, we will identify
whether regeneration in adult frogs fails due to lack of neural progenitors, failure to initiate chromatin
remodeling, or failure to upregulate neuronal morphogenesis genes. By systematically characterizing the
events that define regeneration competence in Xenopus, we expect to identify molecular mechanisms that can
be targeted for more effective therapeutics in human spinal cord injury pa...

## Key facts

- **NIH application ID:** 10208975
- **Project number:** 5R01NS099124-05
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** Andrea Elizabeth Wills
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $334,201
- **Award type:** 5
- **Project period:** 2017-07-15 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10208975

## Citation

> US National Institutes of Health, RePORTER application 10208975, Transcriptional regulatory mechanisms of vertebrate regeneration (5R01NS099124-05). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10208975. Licensed CC0.

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