# A Cross-scale analysis of cell-ECM adhesion in early spinal column development

> **NIH NIH R01** · YALE UNIVERSITY · 2024 · $487,559

## Abstract

The tailbud is the posterior growth zone of the post-gastrulation vertebrate embryo containing the neural and
mesodermal progenitors of the spinal column. The posterior neural tube undergoes convergence along the
medial-lateral axis while extending posteriorly, and failure of neural tube convergence leads to birth defects such
as spina bifida. The left and right paraxial mesoderm are assembled from motile mesodermal progenitors and
subsequently segmented into somites. Failure to segment the paraxial mesoderm or maintain bilateral symmetry
leads to birth defects such as congenital scoliosis. This project uses zebrafish as a model to study the molecular
biophysics and systems morphogenesis in early spinal column development. The lab recently found that inter-
tissue adhesion mediated by the extracellular matrix (ECM) protein Fibronectin mechanically couples the neural
tube and paraxial mesoderm. This inter-tissue adhesion resists convergence of the neural tube which
predisposes the embryo to spina bifida. However, inter-tissue adhesion ensures bilaterally symmetric
morphogenesis of the paraxial mesoderm and thus prevents scoliosis. The interfaces between the neural tube
and the left and right paraxial mesoderm resemble adhesive lap joints which are used in engineering to efficiently
bond two objects. This project uses transgenic zebrafish to examine how the medial-lateral lap joint mechanics
are maintained (Fibronectin acts as a glue) while the neural tube simultaneously slides posteriorly relative to the
mesoderm (Fibronectin acts as a grease). Integrin heterodimers are the primary cell surface receptors for the
ECM and are central to cell and tissue mechanics because they link the ECM to the actomyosin cytoskeleton.
The lab has studied integrin activity in early spinal column development using proteomics, an in vivo FRET-FLIM
assay for Integrin conformational changes, and FCS/FCCS to measure integrin intra-heterodimer affinities in
vivo. The lab found that Integrin 51 and V1 are the two main Fibronectin receptors at this stage of zebrafish
development and that intra-heterodimer affinity sets the threshold for integrin activation. Here, the project will
quantify the molecular dynamics of single heterodimers in the neural tube and paraxial mesoderm using a new
single molecule spectroscopy and machine learning protocol that we have developed. For the first time, we can
measure the movement and conformational dynamics of a single protein in a living embryo.

## Key facts

- **NIH application ID:** 10903235
- **Project number:** 1R01HD115298-01
- **Recipient organization:** YALE UNIVERSITY
- **Principal Investigator:** SCOTT A HOLLEY
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $487,559
- **Award type:** 1
- **Project period:** 2024-08-15 → 2029-07-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10903235

## Citation

> US National Institutes of Health, RePORTER application 10903235, A Cross-scale analysis of cell-ECM adhesion in early spinal column development (1R01HD115298-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10903235. Licensed CC0.

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