TCF3 and infection: For APEX2-mediated proximity labeling, 293iMAAP2−APEX2 and 293iAPEX2 cells were infected with an MAAP mutant virus (AAV2ΔMAAP) with transfection of pHelper that expresses adenovirus helper genes, E2a, E4orf6, and VA. 11AAV2ΔMAAP-infected cells had Dox added at 16 h post-infection (hpi).