# Mechanisms patterning the midface

> **NIH NIH R01** · UNIVERSITY OF COLORADO DENVER · 2024 · $426,479

## Abstract

PROJECT SUMMARY/ABSTRACT: The long-term objective of this proposal is to understand formation of the
midface skeleton, both during normal development, and in human genetic disease conditions. The midface
consists of the structures around the nose, the eye, and the upper jaw. Human genetic disorders, like
frontonasal dysplasia, affect these midface structures. Specifically, the ALX transcription factor encoding genes
have been implicated in multiple types of frontonasal dysplasia. Uniquely, we model these diseases in
zebrafish by using genetic mutants. We propose that the ALX genes function to specify an identity code which
patterns the vertebrate midface. Our model draws from examples like the DLX and HOX codes, which specify
identity in the dorsoventral and anteroposterior axes of the craniofacial skeleton, respectively. We propose
three specific aims to test our innovative “alx-bullseye code” hypothesis, that nested alx gene expression
directly regulates frontonasal skeletal identity. In Aim 1 we define the skeletal structures arising from the
alx-bullseye code in wild types using in situ hybridization, live cell tracking, and lineage tracing. Aim 2 will
determine whether alx gene combinations function to specify frontonasal identity. To identify these functions,
we will compare wild types to alx mutants examining gene expression, skeletal cell differentiation, and
misexpression phenotypes. Aim 3 will uncover how alx genes molecularly control cellular identity. We will
examine an in vivo Alx direct transcriptional reporter, ChIP-seq to identify Alx protein occupancy across the
genome, and Hi-C to reveal enhancer-promoter contacts mediated by Alx. Significance of this proposal is high,
the genes that we propose function in the alx bullseye code have direct human orthologs that are associated
with midface dysmorphologies. This proposal is innovative, as there has not yet been a patterning code
proposed for the vertebrate midface. Success of this proposal will enhance our understanding of midface
craniofacial development and human disease. By using the strengths of the zebrafish system to elucidate the
molecular, cellular, and genetic mechanisms underlying frontonasal dysplasia, we are fulfilling the mission of
the NIDCR to improve human health through research.

## Key facts

- **NIH application ID:** 10930949
- **Project number:** 5R01DE030448-02
- **Recipient organization:** UNIVERSITY OF COLORADO DENVER
- **Principal Investigator:** James Tucker Nichols
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $426,479
- **Award type:** 5
- **Project period:** 2023-09-18 → 2028-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10930949

## Citation

> US National Institutes of Health, RePORTER application 10930949, Mechanisms patterning the midface (5R01DE030448-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10930949. Licensed CC0.

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