American Society of Hematology

Figure 6

$Figure 6. Hematopoiesis pathway regulation on spi1 knockdown and in myeloid cells of a developing embryo at 28 hpf. Expression profiles of the spi1 knockdown embryos and GFP+ myeloid fractions at 28 hpf are simultaneously mapped on a schematic representation of hematopoiesis in zebrafish embryos based on the current knowledge of this process19,42,43 and including the novel macrophage-specific markers identified in this study. The primitive wave of hematopoiesis in zebrafish initiates at 2 distinct sites. At the anterior lateral plate mesoderm (ALPM), hemangioblasts (H) differentiate into myeloid cells (M) or endothelial cells (EC). At the second site, the posterior lateral plate mesoderm (PLPM), which later converts into the intermediate cell mass (ICM), hemangioblasts give rise to erythroid cells (E) and also ECs. In a transient wave of hematopoiesis occurring in posterior blood island (PBI), the EMPs, which are the first multipotent hematopoietic progenitor cells, differentiate into either myeloid or erythroid cells. The definitive wave of hematopoiesis starts in the aorta-gonad-mesonephros (AGM), where hemogenic endothelium (HE) gives rise to hematopoietic stem cells (HSC) and ECs. Gene boxes are color-coded with the microarray data from spi1 knockdown on the left and GFP+ myeloid data on the right side. Expression of gene csf1r was determined by quantitative RT-PCR as the microarray contained only one probe for that gene, and it did not return a significant result. Up-regulation is indicated in yellow, down-regulation in blue, and no significant change in white. Genes marked by asterisks are the genes that were both down-regulated in spi1 knockdown embryos and enriched in the spi1-GFP myeloid cell fraction, and are the focus of this study. It should be noted that it is currently unknown to what extent the microarray expression data from 28-hpf embryos can be extrapolated to later waves of hematopoiesis. Macrophage specificity of cxcr3.2 in embryos is based on colocalization data at 28 hpf, and macrophage specificity of mpeg1, mfap4, and ptpn6 is based on colocalization studies at 28 and 48 hpf.$

Hematopoiesis pathway regulation on spi1 knockdown and in myeloid cells of a developing embryo at 28 hpf. Expression profiles of the spi1 knockdown embryos and GFP⁺ myeloid fractions at 28 hpf are simultaneously mapped on a schematic representation of hematopoiesis in zebrafish embryos based on the current knowledge of this process^19,42,43 and including the novel macrophage-specific markers identified in this study. The primitive wave of hematopoiesis in zebrafish initiates at 2 distinct sites. At the anterior lateral plate mesoderm (ALPM), hemangioblasts (H) differentiate into myeloid cells (M) or endothelial cells (EC). At the second site, the posterior lateral plate mesoderm (PLPM), which later converts into the intermediate cell mass (ICM), hemangioblasts give rise to erythroid cells (E) and also ECs. In a transient wave of hematopoiesis occurring in posterior blood island (PBI), the EMPs, which are the first multipotent hematopoietic progenitor cells, differentiate into either myeloid or erythroid cells. The definitive wave of hematopoiesis starts in the aorta-gonad-mesonephros (AGM), where hemogenic endothelium (HE) gives rise to hematopoietic stem cells (HSC) and ECs. Gene boxes are color-coded with the microarray data from spi1 knockdown on the left and GFP⁺ myeloid data on the right side. Expression of gene csf1r was determined by quantitative RT-PCR as the microarray contained only one probe for that gene, and it did not return a significant result. Up-regulation is indicated in yellow, down-regulation in blue, and no significant change in white. Genes marked by asterisks are the genes that were both down-regulated in spi1 knockdown embryos and enriched in the spi1-GFP myeloid cell fraction, and are the focus of this study. It should be noted that it is currently unknown to what extent the microarray expression data from 28-hpf embryos can be extrapolated to later waves of hematopoiesis. Macrophage specificity of cxcr3.2 in embryos is based on colocalization data at 28 hpf, and macrophage specificity of mpeg1, mfap4, and ptpn6 is based on colocalization studies at 28 and 48 hpf.

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