Protein Science Laboratory of Ministry of Education, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, China.
Blood. 2009 Dec 24;114(27):5464-72. doi: 10.1182/blood-2009-06-227777. Epub 2009 Oct 28.
Metastasis-associated antigens 1/2/3 (Mta1/2/3) are components of nucleosome remodeling and deacetylase (NuRD) complexes and have been found to play roles in embryonic development and homeostasis. However, their functions in primitive hematopoiesis are unknown. In this study, we demonstrate that knockdown of mta3 by antisense morpholinos abolishes primitive hematopoietic lineages and causes abnormal angiogenesis in zebrafish embryos. However, the expression of the pronephric duct and paraxial mesoderm markers is unaltered and the specification of angioblasts is unaffected in mta3 morphants. The results suggest that mta3 is specifically required for primitive hematopoiesis. Furthermore, inhibition of deacetylase activity with the inhibitors valproic acid (VPA) or trichostatin A (TSA) in zebrafish embryos completely blocks primitive hematopoiesis, resulting in hematopoietic defects almost identical to those seen in mta3 morphants. Importantly, overexpression of scl or scl and lmo2, 2 master genes for primitive hematopoiesis, is able to overturn effects of mta3 knockdown or VPA/TSA treatment; and overexpression of mta3, and human MBD3 or HDAC1, 2 other components of NuRD complex, enhances the expression of scl and lmo2 in the posterior lateral plate mesoderm during early primitive hematopoiesis. We conclude that Mta3-NuRD complex is essential for the initiation of primitive hematopoiesis. Thus, our findings provide new insight into the regulatory hierarchy of primitive hematopoiesis in vertebrates.
转移相关抗原 1/2/3（Mta1/2/3）是核小体重塑和去乙酰化酶（NuRD）复合物的组成部分，已被发现在胚胎发育和体内平衡中发挥作用。然而，它们在原始造血中的功能尚不清楚。在这项研究中，我们证明通过反义形态发生素来敲低 mta3 会使原始造血谱系消失，并导致斑马鱼胚胎中的异常血管生成。然而，mta3 形态发生体中肾导管和轴旁中胚层标记物的表达没有改变，血管母细胞的特化不受影响。结果表明 mta3 是原始造血所必需的。此外，用抑制剂丙戊酸（VPA）或曲古抑菌素 A（TSA）抑制去乙酰化酶活性在斑马鱼胚胎中完全阻断原始造血，导致造血缺陷几乎与 mta3 形态发生体中所见完全相同。重要的是，scl 或 scl 和 lmo2 的过表达，2 个原始造血的主基因，能够推翻 mta3 敲低或 VPA/TSA 处理的影响；并且 mta3、人 MBD3 或 HDAC1 的过表达，NuRD 复合物的另外 2 个组成部分，增强了 scl 和 lmo2 在早期原始造血中的后侧板中胚层的表达。我们得出结论，Mta3-NuRD 复合物对于原始造血的起始是必需的。因此，我们的发现为脊椎动物原始造血的调控层次结构提供了新的见解。
