生物谷报道：在胚胎发育过程中血液的形成（造血作用）有两个已经得到承认的阶段：一个是最初的“原始”阶段，发生在胚胎外卵黄囊中，向早期胚胎提供营养；另一个是“最后”阶段，开始于胚胎中一个被称为“大动脉-性腺-中肾”（aorta-gonad-mesonephro）的区域。关于最后造血细胞群的来源是局部的还是外部的（即由从卵黄囊中向内迁移的前体细胞衍生而来）长期存在争论。一项新
的非入侵性细胞跟踪研究与当前的正统观点产生抵触，该研究结果表明，卵黄囊的确是成年造血干细胞的来源。这项研究结果发表于最新一期的《Nature》杂志上。
关于血液供应起源的知识，也许对在培养中生成血液干细胞的研究工作有意义，并且还有可能用于治疗工作。
FIGURE 1. Embryonic expression of Runx1 and analysis of inducible Runx1-dependent cell tagging.
Left column: representative -gal staining of Runx1lacZ/wt embryos at the designated age. Right column: representative (four independent experiments) staining of E11.5–E12.0 Runx1Cre/wt:Rosa26R26R/wt embryos activated at the indicated age by a single injection of 4'OHT. Insets: I, E7.5-tagged cells in the blood circulation of an E11.5–E12 embryo, higher magnification; II, accumulation of E7.5-tagged blood cells in hepatic sinusoids of a E11.5–E12.0 embryo; III, -gal/Runx1+ yolk sac cells enter the embryo proper at E8.25–E8.5; IV, the same cells in the embryo circulation at E8.5; V, about half of E9.5-activated embryos displayed intensive staining around the dorsal aorta at E11.5–E12.0. Scale bars represent 150 m in images of E6.5–E8.5 embryos and insets I–IV; 0.5 mm in images of E9.5 and E12.5 embryos; 50 m in inset V.
原文出处：
Nature Volume 446 Number 7139
Cell tracing shows the contribution of the yolk sac to adult haematopoiesis p1056
Igor M. Samokhvalov, Natalia I. Samokhvalova & Shin-ichi Nishikawa
doi:10.1038/nature05725
Abstract | Full Text | PDF (921K) | Supplementary information
See also: Editor's summary | News and Views by Ueno & Weissman
作者简介：
Shin-Ichi NISHIKAWA
(M. D., Ph. D.)
Research Areas:
Stem cell system is required for all tissues where mature cells are constitutively lost. In the stem cell system, the cell loss is replenished by regulating the survival, proliferation, and differentiation of the stem cells. I has been suggested that these processes are regulated by surrounding microenvironment, which has been designated the stem cell niche. However, molecular and cellular mechanisms underlying the stem cell niche is largely unknown. We aim at understanding the molecular mechanisms underlying the niche supporting stem cell system. While we are focusing on the melanocyte stem cell system at this moment, we want to extend findings derived from this sytem to other stem cell systems. In addtion, we are working on the molecular mechanisms regulating cell specification towards mesodermal lineages using ES cell differentiation system.
Research subjects:
(1) Investigation of the stem cell niche
(2) Investigation of stem cell plasticity
(3) Elucidation of the regulation mechanisms underlying mesoderm specification
List of selected publications:
(1) Uemura, A., Kusuhara, S., Wiegand, S., Yu, R. and Nishikawa, SI.:
"Tlx acts as a proangiogenic switch by regulating extracellular assembly of fibronectin materices in retinal astrocytes."
The Journal of Clinical Investigation 116, 369-377 (2006)
(2) Mak, S., Moriyama, M., Nishioka, E., Osawa, M. and Nishikawa, SI.:
"Indispensable role of Bcl2 in the development of the melanocyte stem cell."
Developmental Biology 291, 144-153 (2006)
(3) Takebe, A., Era, T., Okada, M., Jakt, L.M., Kuroda, Y. and Nishikawa, SI.:
"Microarray analysisi of PDGFRα+ populations in ES cell differentiation culture identifies genes involved in differentiation of mesoderm and mesenchyme including ARID3b that is essential for development of embryonic mesenchymal cells."
Developmental Biology 293, 25-37 (2006)
(4) Moriyama, M., Osawa, M., Mak, S., Ohtsuka, T., Yamamoto, N., Han, H., Delmas, V., Kageyama, R., Beermann, F., Larue, L. and Nishikawa, SI.:
"Notch signaling via Hes1 transcription factor maintains survival of melanoblasts and melanocyte stem cells."
The Journal of Cell Biology 173 (3), 333-339 (2006)
(5) Kobayashi, K., Era, T., Takebe, A., Jakt, L.M. and Nishikawa, SI.:
"ARID3B Induces Malignant Transformation of Mouse Embryonic Fibroblasts and is Strongly Associated with Malignant Neuroblastoma."
Cancer Res 66 (17), 8331-8336 (2006)
