For this, we introduced TwinStrep-tagged Shld1 and Shld3 transgenes into Shld1−/− and Shld3−/− CH12-F3 mouse B cell lymphoma cell lines, respectively, and validated functional complementation at the level of rescued IgM-to-IgA class switching in stimulated cell cultures (Extended Data Fig. 2a,b). The gene discussed is CD79A; the disease is B-cell non-Hodgkin lymphoma.