Hemangioblast commitment in the avian allantois:: Cellular and molecular aspects
Hemangioblast commitment in the avian allantois:: Cellular and molecular aspects
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DOI：
10.1006/dbio.2001.0362
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发表时间：
2001-10-01
影响因子：
2.7
通讯作者：
Jaffredo, T
中科院分区：
文献类型：
--
作者：
Caprioli, A;Minko, K;Jaffredo, T
我们最近发现，尿囊作为一个网站生产造血和内皮细胞能够殖民移植宿主的骨髓。在这里，我们报告了一些早期的细胞学和分子生物学过程发生在尿囊芽，这可能是参与生产成血管细胞和造血细胞的详细调查。我们发现，尿囊经历了一个程序，其特征在于几个“成血管细胞”基因的突出表达的中胚层伴随着其他基因模式在相关的内胚层。VEGF-R2，至少从阶段HH 17开始，被表达，随后不久是转录因子加塔-2、SCL/tal-1和加塔-1。血岛样结构分化，包含CD 45（+）细胞和积累血红蛋白的细胞;这些结构看起来完全像卵黄囊中的血岛。这个造血过程发生在连接尿囊和胚胎的血管网建立之前。就内胚层而言，在肠后门在解剖学上变得不同之前，在尿囊将分化的区域中发现了加塔-3 mRNA。在芽长出之前不久，加塔-2在内胚层中表达，同时，成血管细胞程序在中胚层中开始。至少在E8之前检测到加塔-3，在E3之前检测到加塔-2，E3是检查该因子的最后阶段。使用体外培养，我们表明，尿囊芽，解剖出芽和胚胎的其余部分之间的循环建立之前，产生的红细胞的最终谱系。此外，利用鸡和鹌鹑胚胎之间的异源移植，我们证明了尿囊血管网络的发展从内在的祖细胞。总之，这些结果扩展了我们早期关于中胚层向尿囊中内皮和造血谱系的承诺的发现。在造血细胞出现时器官形成和内胚层特化的背景下，检测到局限于前尿囊区和尿囊芽的内胚层的显著加塔-3表达，随后检测到加塔-2表达，这是一个令人感兴趣的新信息。(C)北京：科学出版社.
We recently identified the allantois as a site producing hemopoietic and endothelial cells capable of colonizing the bone marrow of an engrafted host. Here, we report a detailed investigation of some early cytological and molecular processes occurring in the allantoic bud, which are probably involved in the production of angioblasts and hemopoietic cells. We show that the allantois undergoes a program characterized by the prominent expression of several "hemangioblastic" genes in the mesoderm accompanied by other gene patterns in the associated endoderm. VEGF-R2, at least from stage HH17 onward, is expressed and is shortly followed by transcription factors GATA-2, SCL/tal-1, and GATA-1. Blood island-like structures differentiate that contain both CD45(+) cells and cells accumulating hemoglobin; these structures look exactly like blood islands in the yolk sac. This hemopoietic process takes place before the establishment of a vascular network connecting the allantois to the embryo. As far as the endoderm is concerned, GATA-3 mRNA is found in the region where allantois will differentiate before the posterior instestinal portal becomes anatomically distinct. Shortly before the bud grows out, GATA-2 was expressed in the endoderm and, at the same time, the hemangioblastic program became initiated in the mesoderm. GATA-3 is detected at least until E8 and GATA-2 until E3 the latest stage examined for this factor. Using in vitro cultures, we show that allantoic buds, dissected out before the establishment of circulation between the bud and the rest of the embryo, produced erythrocytes of the definitive lineage. Moreover, using heterospecific grafts between chick and quail embryos, we demonstrate that the allantoic vascular network develops from intrinsic progenitors. Taken together, these results extend our earlier findings about the commitment of mesoderm to the endothelial and hemopoietic lineages in the allantois. The detection of a prominent GATA-3 expression restricted to the endoderm of the preallantoic region and allantoic bud, followed by that of GATA-2, is an interesting and novel information, in the context of organ formation and endoderm specification in the emergence of hemopoietic cells. (C) 2001 Academic Press.