Supplementary MaterialsFigure 1source data 1: Results of the RNAi ligand screen RNAi was expressed in cardiac cells by using the and/or driver. this condition was not tested. Most RNAi lines that gave a modification in crystal cell index with the driver were also analyzed with another cardiac cell driver and proPO antibody immunostainings were performed to visualize crystal cells. Finally, for all those RNAi lines that led to a defect in crystal cell differentiation with the driver, in situ hybridizations were performed and the index was established. elife-64672-fig1-data1.xlsx (19K) GUID:?BAE7D7B9-5CE8-44CA-AE75-584D28E8C3D6 Physique 1source data 2: Results of the RNAi ligand screen. elife-64672-fig1-data2.xlsx (16K) GUID:?A680D119-CDD0-42EB-B9FB-3CABA219976B Physique 1figure supplement 1source data 1: RNAi screen quantification data. elife-64672-fig1-figsupp1-data1.xlsx (67K) GUID:?51412052-FF99-447E-B967-133B0EF41FC6 Physique 2source data 1: Quantification of Physique 2. elife-64672-fig2-data1.xlsx (17K) GUID:?FD486CFF-E772-4BCD-B98D-240FE476B8D4 Physique 2figure supplement 1source data 1: Quantification of Physique 2figure supplement 1. elife-64672-fig2-figsupp1-data1.xlsx (15K) GUID:?EC598722-C1EE-4AEE-BC28-5E7FC3709F2A Physique 2figure supplement 2source data 1: Quantification of Physique 2figure supplement 2. elife-64672-fig2-figsupp2-data1.xlsx (15K) GUID:?16397013-BEDF-45CF-B288-987B34A9AFB9 Figure 3source data 1: Quantification of Figure 3. elife-64672-fig3-data1.xlsx (19K) GUID:?98001155-DDCF-4520-9759-538F138AEB8C Physique 3figure supplement 1source data 1: Quantification of Physique 3figure supplement 1. elife-64672-fig3-figsupp1-data1.xlsx (14K) GUID:?38DB5E09-0BB8-404F-85B6-00321BD0BE96 Figure 4source data 1: Quantification of Figure 4. elife-64672-fig4-data1.xlsx (12K) GUID:?B4E510AC-2780-4653-9952-C12EF6E2502A Physique 4figure supplement 1source data 1: Quantification of Physique 4figure supplement 1. elife-64672-fig4-figsupp1-data1.xlsx (12K) GUID:?CA1C6A30-FC9B-4BB3-B5DA-7D12694789E3 Figure 5source data 1: Quantification of Figure 5. elife-64672-fig5-data1.xlsx (18K) GUID:?CBECEFCA-0303-4088-B4EE-6681AE37C2C6 Physique 5figure supplement 1source data 1: Quantification of Physique 5figure supplement 1. elife-64672-fig5-figsupp1-data1.xlsx (11K) GUID:?464DCC34-A962-4F30-AFF3-825055664F1D Transparent reporting form. elife-64672-transrepform.docx (249K) GUID:?62198625-F5CE-4080-B771-420D48BC5003 Data Availability StatementAll data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for all figures. Abstract In adult mammals, hematopoiesis, the production of blood cells from hematopoietic stem and RXRG progenitor L189 cells (HSPCs), is usually tightly regulated by extrinsic signals from the microenvironment called niche. Bone marrow HSPCs are heterogeneous and controlled L189 by both endosteal and vascular niches. The Drosophila hematopoietic lymph gland is located along the cardiac tube which corresponds to the vascular system. In the lymph gland, the niche called Posterior Signaling Center controls only a subset of the heterogeneous hematopoietic progenitor population indicating that additional signals are necessary. Here we report that this vascular system acts L189 as a second niche to control lymph gland homeostasis. The FGF ligand Branchless produced by vascular cells activates the FGF pathway in hematopoietic progenitors. By regulating intracellular calcium levels, FGF signaling maintains progenitor pools and prevents blood cell differentiation. This study reveals that two niches contribute to the control (driver. The number of genes corresponding to the different classes of phenotype is usually given. Subsequent panels illustrate the control and observed lymph gland defects (c, d, g, j). Anterior lobe and PSC are delimited by white and yellow dashed lines, respectively. Black-cell-GFP (BcGFP, white) labels crystal cells and Antp (black) the PSC. (c, d, g, j) BcGFP is in green; (e, h, k) PSC cell numbers; (f, i, l) Crystal cell index. (cCf) Reducing in cardiac cells (d, d) augments PSC cell number (e) without affecting crystal cell differentiation (f); this defines class 1. (gCi) Knocking down in cardiac cells (g, g) decreases PSC cell number (h) and increases crystal cell index (i); this defines class 2. (jCl) Reducing in cardiac cells (j, j) does not modify PSC cell number (k) but increases crystal cell differentiation (l); this defines class 3. (m, n) (red) labels core progenitors. Decrease in expression is observed when is usually knocked down in cardiac cells. (o) index. For all those quantifications and figures, statistical analysis and/or driver. Crystal cells were labeled by BcGFP, PSC cells were immune-stained with Antp antibody, and to visualize the core progenitors in situ hybridization was performed. In most cases, 2 RNAi lines were tested per ligand, and at least 15 lymph glands per RNAi were analyzed. Crystal cell index and PSC cell number were established. The green and red colored boxes indicate an increase and a decrease, respectively, compared to the control. Black dashes indicate that no difference was observed compared to the control. A white box indicates that this condition was not tested. Most RNAi lines that gave a modification in crystal cell index with the driver were also analyzed with another cardiac cell driver and proPO antibody immunostainings were performed to visualize crystal cells. Finally, for all those RNAi lines that led to a defect in crystal cell differentiation with the driver, in situ hybridizations were performed and the index was established. Click here to view.(19K, xlsx) Physique 1source data 2.Results of the RNAi ligand screen.Click here to view.(16K, xlsx) Physique 1figure supplement 1. Open in a separate window Expression pattern of and driver in.