QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online 24 October 2007
doi: 10.1242/dev.012385

This Article Figures Only Full Text Full Text (PDF) Supplementary Material All Versions of this Article: dev.012385v1 134/23/4147    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bertrand, J. Y. Articles by Traver, D. Search for Related Content PubMed PubMed Citation Articles by Bertrand, J. Y. Articles by Traver, D.

Definitive hematopoiesis initiates through a committed erythromyeloid progenitor in the zebrafish embryo

Julien Y. Bertrand^*, Albert D. Kim^*, Emily P. Violette, David L. Stachura, Jennifer L. Cisson and David Traver

Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093-0380, USA

Author for correspondence (e-mail: dtraver{at}ucsd.edu)

Accepted 5 September 2007

Shifting sites of blood cell production during development is common across widely divergent phyla. In zebrafish, like other vertebrates, hematopoietic development has been roughly divided into two waves, termed primitive and definitive. Primitive hematopoiesis is characterized by the generation of embryonic erythrocytes in the intermediate cell mass and a distinct population of macrophages that arises from cephalic mesoderm. Based on previous gene expression studies, definitive hematopoiesis has been suggested to begin with the generation of presumptive hematopoietic stem cells (HSCs) along the dorsal aorta that express c-myb and runx1. Here we show, using a combination of gene expression analyses, prospective isolation approaches, transplantation, and in vivo lineage-tracing experiments, that definitive hematopoiesis initiates through committed erythromyeloid progenitors (EMPs) in the posterior blood island (PBI) that arise independently of HSCs. EMPs isolated by coexpression of fluorescent transgenes driven by the lmo2 and gata1 promoters exhibit an immature, blastic morphology and express only erythroid and myeloid genes. Transplanted EMPs home to the PBI, show limited proliferative potential, and do not seed subsequent hematopoietic sites such as the thymus or pronephros. In vivo fate-mapping studies similarly demonstrate that EMPs possess only transient proliferative potential, with differentiated progeny remaining largely within caudal hematopoietic tissue. Additional fate mapping of mesodermal derivatives in mid-somitogenesis embryos suggests that EMPs are born directly in the PBI. These studies provide phenotypic and functional analyses of the first hematopoietic progenitors in the zebrafish embryo and demonstrate that definitive hematopoiesis proceeds through two distinct waves during embryonic development.

Key words: Erythromyeloid progenitor, Hematopoiesis, Hematopoietic progenitor cells, Zebrafish

This article has been cited by other articles:

				J. Y. Bertrand, A. D. Kim, S. Teng, and D. Traver CD41+ cmyb+ precursors colonize the zebrafish pronephros by a novel migration route to initiate adult hematopoiesis Development, May 15, 2008; 135(10): 1853 - 1862. [Abstract] [Full Text] [PDF]

				D. Carradice and G. J. Lieschke Zebrafish in hematology: sushi or science? Blood, April 1, 2008; 111(7): 3331 - 3342. [Abstract] [Full Text] [PDF]

				S. Hutchinson and N. S. Trede Stem-cell trafficking at vascular borders Blood, February 1, 2008; 111(3): 975 - 976. [Full Text] [PDF]