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Development. 2015 Mar 15;142(6):1050-61. doi: 10.1242/dev.119180.

Gata2b is a restricted early regulator of hemogenic endothelium in the zebrafish embryo.

Author information

1
Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA.
2
Institute of Molecular Life Sciences, University of Zürich, Zürich, Switzerland.
3
Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA.
4
University of Massachusetts at Worcester, Worcester, MA 01605, USA.
5
Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA Department of Hematology, St Jude Children's Research Hospital, Memphis, TN 38105, USA.
6
Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA Section of Cell and Developmental Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093, USA dtraver@ucsd.edu.

Abstract

The adult blood system is established by hematopoietic stem cells (HSCs), which arise during development from an endothelial-to-hematopoietic transition of cells comprising the floor of the dorsal aorta. Expression of aortic runx1 has served as an early marker of HSC commitment in the zebrafish embryo, but recent studies have suggested that HSC specification begins during the convergence of posterior lateral plate mesoderm (PLM), well before aorta formation and runx1 transcription. Further understanding of the earliest stages of HSC specification necessitates an earlier marker of hemogenic endothelium. Studies in mice have suggested that GATA2 might function at early stages within hemogenic endothelium. Two orthologs of Gata2 exist in zebrafish: gata2a and gata2b. Here, we report that gata2b expression initiates during the convergence of PLM, becoming restricted to emerging HSCs. We observe Notch-dependent gata2b expression within the hemogenic subcompartment of the dorsal aorta that is in turn required to initiate runx1 expression. Our results indicate that Gata2b functions within hemogenic endothelium from an early stage, whereas Gata2a functions more broadly throughout the vascular system.

KEYWORDS:

Gata2; Hematopoietic stem cell; Hemogenic endothelium; Notch; Subfunctionalization

PMID:
25758220
PMCID:
PMC4360177
DOI:
10.1242/dev.119180
[Indexed for MEDLINE]
Free PMC Article

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