Fig 2: Two JAK1 mutations found in the patient.(a) Patient's family tree. (b) Sequence chromatograms showing two mutations in the JAK1 gene. (c) Domain structure of the JAK1 protein. (d) JAK1 pseudokinase (JH2) and kinase (JH1) domains modelled using the published structure of TYK2 pseudokinase and kinase domains (PDB 4OLI). Pro733 and Pro832 are shown in red and green, respectively.

Fig 3: Detection of NPM1–TYK2 in tumors and lymphoma cell infiltration induced hepatosplenomegaly.A, B Detection of NPM1–TYK2 (FLAG) in tumors by immunostaining and RT-qPCR. Columns represent the mean of three independent experiments; bars represent the SEM. C Hematoxylin and eosin (H&E) staining of sections from tumor tissue demonstrate lymphoma cell infiltration into tumor, spleen, and liver.

Fig 4: Fusion kinase NPM1–TYK2 constitutive activation drives tumorigenicity in in vivo xenograft models.Representative lysates were made from tissue collected from Ba/F3-Vector and transformed Ba/F3–NPM1–TYK2 injected mice. Western blot analysis was performed for NPM1–TYK2 (FLAG), phospho-NPM1–TYK2, phospho-STAT1/3/5, and respective total proteins. β-Actin served as an internal control.

Fig 5: In vitro transformation potential of the NPM1–TYK2 fusion gene.A Detection of overexpressed NPM1–TYK2 mRNA transcript levels in transformed Ba/F3 cells by qRT-PCR. Myla and SU-DHL-1 cell lines were used as positive and negative controls, respectively. Columns represent the mean of three independent experiments; bars represent the SEM. B Subcellular localization of NPM1–TYK2. Ba/F3-Vector and transformed Ba/F3 (NPM1–TYK2) cells were cytospun onto glass slides, fixed, permeabilized, and stained for FLAG antibody and DAPI. Images were acquired with a fluorescent microscope using a 60× oil immersion lens. C Transformation of Ba/F3 cells to IL-3 independent growth. Ba/F3-Vector and transformed Ba/F3 (NPM1–TYK2) cells were grown in RPMI medium in the absence of IL-3. Cell viability from each condition was determined daily by trypan blue exclusion assay. Points represent the mean of three independent experiments; bars represent SEM. ∗∗∗P < 0.0005 was considered as statistically extremely significant. D The clonogenic potential of transformed Ba/F3 (NPM1–TYK2) cells. Ba/F3-Vector and transformed Ba/F3 NPM1–TYK2 cells were mixed with MethoCult medium and plated. After 7 days of incubation, the number of colonies was counted. Columns represent the mean of three independent experiments; bars represent the SEM.