# Transcriptional regulatory landscapes underlying FEZ Formation

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 2021 · $564,900

## Abstract

Summary:
Morphogenesis of vertebrate tissues and organs occurs through well-orchestrated tissue interactions. During
development of the upper jaw, signaling interactions among the forebrain, the facial ectoderm, and the
intervening neural crest cells regulate development of the upper jaw. Our research has revealed that signals
from the brain and the neural crest cells act together to induce expression of Sonic hedgehog (SHH) in the
Frontonasal Ectodermal Zone (FEZ), a signaling center located in the surface ectoderm of the Frontonasal
Process (FNP) that directs patterned growth of the upper jaw anlagen. Our preliminary data also suggest that
Pre-B-cell leukemia homeobox (PBX) transcription factors are involved in inducing and maintaining the pattern
of SHH expression in the FEZ by an interacting genetic network. The research proposed in this application is
designed to uncover the gene regulatory mechanisms that are activated by signals from the forebrain and the
neural crest, as well as, to investigate the role of PBX transcription factors in regulating SHH expression in the
FEZ. Specifically, we hypothesize that 1) SHH signaling from the forebrain induces “competence” in surface
ectoderm cells to express SHH; 2) subsequently, upon arrival, neural crest cells induce transcription of SHH in
competent cells of the FEZ, and 3) PBX transcription factors participate in regulating expression of SHH in the
FEZ. We will test this hypothesis in three specific aims using avian and murine embryos. In each Aim, we will
use chick embryos because they allow us to manipulate the signaling interactions between the brain and the
FEZ (Aim 1), the neural crest cells and the ectoderm (Aim 2), or expression of PBX1 and PBX3 (Aim 3). We
will use a variety of genomic approaches (ATAC-seq, ChIP-seq, GRO-seq) to evaluate changes in chromatin
and activated transcriptional regulatory elements (TREs) at the SHH locus. In Aim 3, we will also assess
morphological, cellular, and molecular outcomes of altering PBX gene expression, and we will use mouse
embryos to take advantage of data already generated in the Selleri laboratory. The results of the work
proposed in this application will shed light on the molecular aspects of facial development, and will aid
understanding of disease processes that occur in this region. Allelic variants in SHH, or SHH pathway
members, are associated with human dysmorphologies of the craniofacial complex in diseases such as
Holoprosencephaly and cleft lip with our without cleft palate. Recently, PBX genes have been identified as risk
variants in patients with craniofacial dysmorphology. Hence, our innovative approach combining studies with a
solid foundation in developmental biology with chromatin analyses will yield information that is directly
applicable to understanding human dysmorphology.

## Key facts

- **NIH application ID:** 10125992
- **Project number:** 5R01DE028324-02
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **Principal Investigator:** Ralph S Marcucio
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $564,900
- **Award type:** 5
- **Project period:** 2020-03-11 → 2025-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10125992

## Citation

> US National Institutes of Health, RePORTER application 10125992, Transcriptional regulatory landscapes underlying FEZ Formation (5R01DE028324-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10125992. Licensed CC0.

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