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Primitive and definitive erythropoiesis in the yolk sac: a bird's eye view

Guojun Sheng1

  • 1Laboratory for Early Embryogenesis, RIKEN Center for Developmental Biology, Kobe, Hyogo, Japan. sheng@cdb.riken.jp

The International Journal of Developmental Biology
|June 22, 2010
PubMed

Insights

The yolk sac is crucial for early red blood cell development in chicken embryos, supporting both primitive and definitive erythropoiesis. Later, bone marrow takes over as the primary site for blood cell formation.

Area of Science:

  • Developmental Biology
  • Hematopoiesis
  • Cell Biology

Background:

  • The yolk sac is the primary site for early red blood cell production in developing chicken embryos.
  • Hematopoiesis transitions from the yolk sac to the bone marrow during embryonic development.

Purpose of the Study:

  • To review the yolk sac's role in the three distinct phases of erythropoiesis.
  • To discuss cell specification in the extraembryonic mesoderm before circulation establishment.

Main Methods:

  • Review of existing literature on embryonic hematopoiesis.
  • Discussion of concepts like blood islands, hemangioblasts, and hemogenic endothelium.

Main Results:

  • The yolk sac serves as the sole niche for primitive erythropoiesis (E1-E5) and a major niche for early definitive erythropoiesis (E5-E12).
  • A developmental transition shifts hematopoiesis to the bone marrow, with intraembryonically-derived cells becoming dominant.

Conclusions:

  • The yolk sac plays a critical, phased role in chicken embryonic erythropoiesis.
  • The chick embryo remains a valuable model for studying developmental hematopoiesis and erythropoiesis.

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