Mukouyama Y, Chiba N, Hara T, Okada H, Ito Y, Kanamaru R, Miyajima A, Satake M, Watanabe T
Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113, Japan.
Dev Biol. 2000 Apr 1;220(1):27-36. doi: 10.1006/dbio.2000.9617.
We examined the role of the AML1 transcription factor in the development of hematopoiesis in the paraaortic splanchnopleural (P-Sp) and the aorta-gonad-mesonephros (AGM) regions of mouse embryos. The activity of colony-forming units of colonies from the P-Sp/AGM region was reduced severalfold by heterozygous disruption of the AML1 gene, indicating that AML1 functioned in a dosage-dependent manner to generate hematopoietic progenitors. In addition, no hematopoietic progenitor activity was detected in the P-Sp/AGM region of embryos with an AML1 null mutation. Similar results were obtained when a dispersed culture was first prepared from the P-Sp/AGM region before assay of the activity of the colony-forming units. In a culture of cells with the AML1(+/+) genotype, both hematopoietic and endothelial-like cell types emerged, but in a culture of cells with the AML1(-/-) genotype, only endothelial-like cells emerged. Interestingly, introduction of AML1 cDNA into the P-Sp/AGM culture with the AML1(-/-) genotype partially restored the production of hematopoietic cells. This restoration was observed for cultures prepared from 9.5-day postcoitum (dpc) embryos but not for cultures prepared from 11.5-dpc embryos. Therefore, the population of endothelial-like cells capable of growing in the AML1(-/-) culture would appear to contain inert but nonetheless competent hematogenic precursor cells up until at least the 9.5-dpc period. All these results support the notion that the AML1 transcription factor functions to develop and maintain hematogenic precursor cells in the embryonic P-Sp/AGM region.
我们研究了AML1转录因子在小鼠胚胎的主动脉旁脏壁（P-Sp）和主动脉-性腺-中肾（AGM）区域造血发育中的作用。AML1基因杂合性破坏使来自P-Sp/AGM区域的集落形成单位的集落活性降低了几倍，这表明AML1以剂量依赖的方式发挥作用来产生造血祖细胞。此外，在具有AML1无效突变的胚胎的P-Sp/AGM区域未检测到造血祖细胞活性。当在检测集落形成单位活性之前首先从P-Sp/AGM区域制备分散培养物时，也获得了类似的结果。在具有AML1(+/+)基因型的细胞培养物中，造血细胞和内皮样细胞类型均出现，但在具有AML1(-/-)基因型的细胞培养物中，仅出现内皮样细胞。有趣的是，将AML1 cDNA导入具有AML1(-/-)基因型的P-Sp/AGM培养物中可部分恢复造血细胞的产生。这种恢复在从妊娠9.5天（dpc）胚胎制备的培养物中观察到，但在从11.5 dpc胚胎制备的培养物中未观察到。因此，能够在AML1(-/-)培养物中生长的内皮样细胞群体似乎至少直到9.5 dpc期都含有惰性但仍有能力的造血前体细胞。所有这些结果支持这样的观点，即AML1转录因子在胚胎P-Sp/AGM区域中发挥作用以发育和维持造血前体细胞。
