Fig. 4. Human and rodent TrkB.T1 immunostaining in normal brain and glioma.

a Receptor schematic of TrkB.FL (kinase domain demonstrated in orange with phosphorylation sites in yellow) and TrkB.T1 highlighting region of antibody specificity (11-amino acid region shown in teal blue). Extracellular domain, transmembrane domain, and first intracellular amino acids common to both variants shown in light green. TrkB.T1 immunohistochemistry shows punctate vesicular staining in normal human (b) and mouse cortex (c) compared with intense diffuse staining in human glioma (b) and mouse glioma (c) with lack of punctate vesicular pattern. Lack of staining in rodent negative control (no primary antibody) and TrkB.T1^−/− cortex demonstrates antibody specificity for TrkB.T1 splice variant. (IDHmut—IDH mutant; 1p19q codel—1p 19 q co-deleted). Immunohistochemistry was performed on independent biological samples of each tumor type, in replicates of 3–5. Representative images were chosen and additional images are shown in Supplementary Fig. 4–6. Photomicrographs are as specified at 40×(scale bar = 200 µm), 200×(scale bar = 50 µm), and 600×(scale bar = 20 µm).