Mta3-NuRD complex is a master regulator for initiation of primitive hematopoiesis in vertebrate embryos

Abstract

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. (Blood. 2009;114:5464-5472) IntroductionHematopoiesis occurs in 2 successive waves, primitive and definitive hematopoiesis in mammals, birds, and teleosts. In mammalian and avian species, the extraembryonic yolk sac is the site for primitive hematopoiesis that produces primitive macrophages and erythrocytes. In contrast, primitive hematopoiesis in zebrafish progresses in the intermediate cell mass (ICM; an intraembryonic trunk region), which is developed from the ventrolateral plate mesoderm and gives rise to erythrocytes and endothelial linage, as well as in rostral blood island, which arises from the cephalic mesoderm and produces macrophages and endothelial cells. 1,2 After the primitive hematopoiesis, definitive hematopoiesis initiates within the ventral wall of dorsal aorta in a region known as aorta-gonad-mesonephros and then transits into fetal liver and bone marrow in mammals, in which long-term hematopoietic stem cells differentiate into erythroid, myeloid, and lymphoid lineages for the life span. 3 Zebrafish definitive hematopoiesis also starts in aortagonad-mesonephros, but later switches to kidney marrow, 3 an analog to bone marrow in mammals.Zebrafish primitive hematopoietic precursors emerge during early segmentation period from the 1-to 2-somite stage through the 5-somite stage, which is marked by the expression in the anterior lateral mesoderm and/or the posterior lateral mesoderm of several hematopoietic transcription factors, including stem cell leukemia (scl)/T-cell acute lymphocytic leukemia 1 (tal1),...

Znf45l affects primitive hematopoiesis by regulating transforming growth factor-β signaling

“…The phenocopy caused by znf45l knockdown is similar to the embryos depleted of β-arrestin1 and mta3 (metastasis-associated protein number3), which were described by Yue et al and Li et al as critical factors for hematopoiesis (4,11). Reasonably, we ask that whether znf45l functions to initial primitive hematopoiesis.…”

Subcellular localization of MTA proteins in normal and cancer cells

“…MTA3 was also reported to be highly expressed in germinal center B lymphocytes, in which MTA3/NuRD physically interacts with BCL-6 and functions to facilitate transcriptional repression by BCL-6 in regulating cell fate during B lymphocyte differentiation [131]. The MTA3/NuRD complex is also essential for the initiation of primitive hematopoiesis in vertebrate embryos [127]. The MTA3/NuRD complex was suggested to function to support the chromatin remodeling required for cohesin loading and G2/M progression [128].…”

“…Like MTA1, MTA3 shows a widespread expression pattern in embryonic and adult tissues [13,127]. However, as it contains EREs in the gene promoter, MTA3 is strictly regulated by ER in breast cancer.…”

Interruption of cenph Causes Mitotic Failure and Embryonic Death, and Its Haploinsufficiency Suppresses Cancer in Zebrafish

“…TUNEL and pH3 Staining-For detection of apoptotic cells in embryos, TUNEL assay was performed using the In Situ Cell Death Detection kit, TMR red (Roche Applied Science), according to the manufacturer's instruction with some modifications (28). The embryos were observed by fluorescence microscopy (Zeiss SteREO Discovery version 20).…”

“…The embryos were observed by fluorescence microscopy (Zeiss SteREO Discovery version 20). Staining of phosphohistone H3 in zebrafish embryos was performed using Ser-10 phosphohistone H3 antibody as described previously (28).…”