A great diversity of ROBO4 expression and regulations identified by data mining and transgene mice.

ROBO4 involves in the stabilization of blood vessel and mediates the migration of hematopoietic stem cell and newborn neuron. However, the patterns of expression and regulation are not quite clear. To resolve this, we analyzed the single cell sequence data, and confirmed that Robo4 mainly expresses in various endothelial cells, but also in epithelial cells, pericytes, and stem or progenitor cells of bone marrow, fibroblast cells/mesenchymal stem cell of adipose tissues, muscle cells and neuron. Robo4 expressions in endothelial cells derived from capillary vessel, tip/stalk/activated endothelial cells were higher than that in artery and large vein (matured endothelial cells). On the other hand, via mining the gene expression data deposited in the NCBI Gene Expression Omnibus database as well as National Genomics Data Center (NGDC), we uncovered that the expression of Robo4 were regulated by different stimulus and variable in diseases' condition.Moreover, we constructed enhanced GFP (eGFP) transgene mouse controlled by Robo4 promoter using CRISPR/CAS9 system. We found GFP signals in many cell types from the embryonic section, confirming a widely expression of Robo4. Together, Robo4 widely and dynamically express in multiple cell types, and can be regulated by diverse factors.