Developmental Expression of dlx5a and chm in Zebrafish

Maïka Harvey; Ben Harrison; Kathleen M. Gilmour; Marc Ekker

doi:10.18192/osurj.v5i2.8052

Developmental Expression of dlx5a and chm in Zebrafish

Authors

Maïka Harvey University of Ottawa, Ottawa, ON, Canada
Ben Harrison University of Ottawa, Ottawa, ON, Canada
Kathleen M. Gilmour University of Ottawa, Ottawa, ON, Canada
Marc Ekker University of Ottawa, Ottawa, ON, Canada

DOI:

https://doi.org/10.18192/osurj.v5i2.8052

Abstract

Zebrafish (Danio rerio) larvae are a powerful model for visualizing early vertebrate gene
expression due to their external development and the conservation of different gene sequences
with human counterparts, allowing them to be useful tools for cross-species comparison. The
dlx5a gene encodes a homeodomain transcription factor expressed in craniofacial and neural
crest-derived regions, whereas chm encodes Rab escort protein 1 (REP-1), which is broadly
required for intracellular trafficking and retinal development. We aimed to characterize the
baseline developmental expression of dlx5a and chm in wild-type zebrafish embryos at 2 and 3
days post-fertilization (dpf). Whole-mount in situ hybridization was performed on
paraformaldehyde-fixed, methanol-stored embryos using digoxigenin-labelled antisense probes
for dlx5a or chm respectively. At 2 dpf, dlx5a staining was detected in distinct domains of the
anterior head and along the body axis, consistent with craniofacial and neural crest-related
patterning regions. By 3 dpf, the dlx5a signal appeared stronger and more extensive in these
domains, reflecting continued development of dlx5a-positive structures. In contrast, chm staining
showed a developmental shift in localization. At 2 dpf, expression was predominantly restricted
to the head region. By 3 dpf, the chm signal became more apparent in the trunk, indicating an
expansion of transcript distribution along the body axis, consistent with its ubiquitous and
essential expression pattern in zebrafish, mice and humans. Together, these qualitative
expression maps establish a developmental baseline for future studies examining how mutations
in chm or dlx5a, or environmental perturbations alter gene localization in relevant zebrafish
models.

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Published

2026-06-17

Issue

Vol. 5 No. 2 (2026)

Section

Undergraduate Science Research Opportunity Abstracts

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