# Building a gene regulatory network-based model for cell fate specification and morphogenesis using a new mollusc model.

> **NIH NIH R35** · UNIVERSITY OF CALIFORNIA, SAN DIEGO · 2020 · $335,781

## Abstract

Project Summary:
Cells are the fundamental units of all biological structures and phenomena—the evolution of
novel phenotypes and physiologies is ultimately the result of changes in cellular characteristics,
especially cell fate specification. Cell fate specification is well understood in established model
systems, and can be described and modelled by building gene regulatory networks (GRNs). It is
not well-understood how gene regulatory networks maintain vs modify their wiring over
evolution, by making and breaking connections between genes. One of the impediments to
making progress in this area is the lack of sophisticated GRNs outside of deuterostomes
(echinoderms, vertebrates, ascidians) and ecdysozoans (nematodes and arthropods). Unlike
these two well-studied clades, the Spiralia/Lophotrochozoa has not been used for GRN
analysis, despite the fact that this monophyletic group includes ~40% of extant animal body
plans, including familiar taxa like annelids and molluscs. Many members of the Spiralia begin
development with a common ground plan sharing a highly stereotyped pattern of spiral cleavage
and homologous cell lineages. Between these species, cell lineages can be homologized at
single-cell resolution across hundreds of millions of years of evolution. Yet Spiralian embryos
ultimately are transformed through morphogenesis into a vast array of diverse adult body
plans. Nowhere else can one undertake systematic comparisons at a single-cell level between
body plans; thus spiralians offer a unique opportunity for comparative developmental biology at
the level of morphology, molecular mechanisms, and homologous cell lineages. This proposal
argues that the slipper snail Crepidula is poised to make significant contributions to GRN
biology by being used to build the first developmental GRN among Spiralians. We outline a
strategy to build a comprehensive developmental gene regulatory network for every cell type
in Crepidula. This research will define: 1) the molecular mechanisms controlling the formation
and function of the Crepidula embryonic organizer and 2) the GRN controlling
gastrulation. Studying cell fate specification and morphogenesis in a wider range of animals will
provide fresh insight into the ways GRNs operate, and will provide a useful comparison for other
model systems.

## Key facts

- **NIH application ID:** 9991865
- **Project number:** 5R35GM133673-02
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN DIEGO
- **Principal Investigator:** Deirdre C Lyons
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $335,781
- **Award type:** 5
- **Project period:** 2019-08-15 → 2024-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9991865

## Citation

> US National Institutes of Health, RePORTER application 9991865, Building a gene regulatory network-based model for cell fate specification and morphogenesis using a new mollusc model. (5R35GM133673-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9991865. Licensed CC0.

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