Figure 4.

Notch1 signaling is upregulated in thymic lymphomas harboring functional p53. a-b, mRNA expression of 5’ and 3’ region of the Notch1 gene. Results were compared between lymphomas and control thymuses from mice of the same genotype. Data are presented as mean ± SE. Each dot represents one mouse. *P<0.05 by Mann-Whitney U test. c, Detection of Type 1 deletions of the Notch1 gene among thymic lymphomas of different genotypes. d, Sequencing results of the Type 1 deletion PCR product. Sanger sequencing showed that Type 1 deletions resulted from a specific gene recombination between the 5’ UTR and Intron 2. e, Summary of intracellular Notch1 (ICN) protein expression, Notch1 mutations, Notch1 Type 1 deletions and Ikzf1 mutations across thymic lymphomas of different genotypes. f, Expression of ICN protein in IR-induced WT lymphoma cells treated with DMSO or the γ-secretase inhibitor DAPT in vitro. Cyclophylin A was used as a control for protein loading. Quantification of Western blot data is shown as ICN/ Cyclophylin A. g, The mRNA expression of 5’ and 3’ regions of Notch1 as well as transcriptional targets of Notch1. Each dot represents one mouse. *P<0.05 by Kruskal-Wallis test.