Hemato-Vascular Specification Requires arnt1 and arnt2 Genes in Zebrafish Embryos

Authors

Hailey E Edwards
Mary Jane Elizalde
Jaclyn P Souder
Daniel A Gorelick

Publication Date

5-1-2023

Journal

Development

DOI

10.1242/dev.200500

PMID

37039097

PMCID

PMC10163348

PubMedCentral® Posted Date

4-28-2023

PubMedCentral® Full Text Version

Post-print

Published Open-Access

yes

Keywords

Animals, Basic Helix-Loop-Helix Transcription Factors, Endothelial Cells, Gene Expression Regulation, Transcription Factors, Zebrafish, Zebrafish Proteins, Aryl Hydrocarbon Receptor Nuclear Translocator, Arnt, Hematopoiesis, Hematovascular specification, Npas4l, Zebrafish

Abstract

During embryonic development, a subset of cells in the mesoderm germ layer are specified as hemato-vascular progenitor cells, which then differentiate into endothelial cells and hematopoietic stem and progenitor cells. In zebrafish, the transcription factor npas4l (cloche) is required for the specification of hemato-vascular progenitor cells. However, it is unclear whether npas4l is the sole factor at the top of the hemato-vascular specification cascade. Here, we show that arnt1 and arnt2 genes are required for hemato-vascular specification. We found that arnt1;arnt2 double mutant zebrafish embryos, but not arnt1 or arnt2 single mutants, lack blood cells and most endothelial cells. arnt1/2 mutants have reduced or absent expression of etsrp and tal1, the earliest known endothelial and hematopoietic transcription factor genes. We found that Npas4l binds both Arnt1 and Arnt2 proteins in vitro, consistent with the idea that PAS domain-containing bHLH transcription factors act in a multimeric complex to regulate gene expression. Our results demonstrate that npas4l, arnt1 and arnt2 act together to regulate endothelial and hematopoietic cell fate, where each gene is necessary, but not sufficient, to drive hemato-vascular specification.

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