GFI1 and infection: To assay the extent to which induced hair cells replicate the mouse primary cochlear hair cell gene expression program, we performed RNA-sequencing on FACS-purified Atoh1-nGFP+ cells generated by overexpression of Six1, Atoh1, Pou4f3, and Gfi1 (SAPG) at 14 days post infection (dpi)(hereafter referred to as iHCs).