Mutations and RNA-binding proteins controlling CD19 splicing and CART-19 therapy resistance: PTBP1 iCLIP2 in NALM-6 cells

We developed a massively parallel reporter assay to determine the splicing effects of all mutations in the region comprising CD19 exons 1-3. Despite the great success of CART-19 (chimeric antigen receptor-armed autologous T-cells) immunotherapy to treat B-cell acute lymphoblastic leukaemia (B-ALL), many patients relapse due to loss of the targeted CD19 epitope. Since epitope loss can be caused by CD19 exon 2 mis-splicing, we set out to learn the regulatory code that controls CD19 alternative splicing. iCLIP2 protocol performed in NALM-6 cell lines in two replicates under two different RNAse I dilution values