Supplementary Figure 7: Colonization of the thymus rudiment by T-IPs in Rbpj-deficient embryos at E11.5.
From: Initial seeding of the embryonic thymus by immune-restricted lympho-myeloid progenitors
Related to main Figure 8. (a,b) Whole mount imaging of a RbpjFl/Fl Vav-Cre+/+ Rag1-GFPTg/+ TS11 embryo. (a) Transverse optical section showing localization of thymic rudiments (arrows) identified by cytokeratin (CK, red). nt, neural tube; *, notochord. Scale bars represent 300 µm. (b) Three-dimensional image of the left and right thymic lobes showing the thymus rudiment surrounded by Rag1-GFP+ (green) T-IPs. Note that the thymus rudiment is connected to the third pharyngeal pouch on one side and to the external ectoderm on the other side. Scale bars represent 50 µm. (c-e) Using the “surfaces” function of Imaris software the thymus rudiment was 3D-reconstructed to allow the quantification of the distances to Rag1-GFP+ cells. Image segmentation (d, e) was made based on cytokeratin fluorescence intensity (c) and morphology (see also Supplementary Fig. 1). Scale bars represent 50 µm. (f,g) Serial transverse optical sections (2.5 µm) of the thymic rudiment region from a RbpjFl/Fl Vav-Cre+/+ Rag1-GFPTg/+ (c, Vav-Cre+/+) and a RbpjFl/Fl Vav-CreTg/+ Rag1-GFPTg/+ (d, Vav-CreTg/+) embryo. Images are representative of 8 and 6 thymic lobes from 4 Vav-Cre+/+ and 3 Vav-CreTg/+ embryos, respectively. Scale bars represent 50 µm. (c-g) TPP, thymus-parathyroid primordium; PE, pharyngeal endoderm; SE, surface ectoderm
