Zhang C, Evans T
Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Dev Genet. 1996;18(3):267-78. doi: 10.1002/(SICI)1520-6408(1996)18:3<267::AID-DVG7>3.0.CO;2-7.
We have investigated the process by which the primitive erythroid cells develop during early vertebrate embryogenesis. Cultured Xenopus animal cap (AC) cells transiently activate the transcription of blood cell regulatory genes GATA-1 and GATA-2 but fail to commit stably to the blood lineage. By contrast, cells of the presumptive ventral marginal zone (VMZ), are committed by the midblastula transition (MBT) to express fully on erythroid program. Growth factor BMP-4, a member of the TGF-beta family of signaling molecules, has been implicated in the process of ventral mesoderm patterning. We show that expression of BMP-4 after MBT is sufficient to induce the blood program fully in AC cells. This includes high level expression of the blood markers SCL and globin, which are not activated in AC cells from uninjected embryos. Likewise, expression of a dominant negative receptor after MBT results in relatively normal embryos, which, however, completely lack differentiated blood cells. Our results are consistent with a role for BMP or BMP-like signaling during gastrulation in the differentiation of embryonic blood.
我们研究了早期脊椎动物胚胎发育过程中原始红细胞的发育过程。培养的非洲爪蟾动物帽（AC）细胞会短暂激活血细胞调节基因GATA-1和GATA-2的转录，但无法稳定地定向分化为血细胞谱系。相比之下，假定腹侧边缘区（VMZ）的细胞在囊胚中期转换（MBT）时就已定向分化，从而完全表达红细胞生成程序。生长因子BMP-4是TGF-β信号分子家族的成员之一，它参与腹侧中胚层模式形成的过程。我们发现，MBT后BMP-4的表达足以在AC细胞中完全诱导血细胞生成程序。这包括血细胞标志物SCL和球蛋白的高水平表达，而在未注射胚胎的AC细胞中这些标志物并未被激活。同样，MBT后显性负受体的表达会产生相对正常的胚胎，然而这些胚胎完全缺乏分化的血细胞。我们的结果与BMP或BMP样信号在原肠胚形成过程中对胚胎血细胞分化所起的作用相一致。
