(A) GFP expression 2 days after transduction. Many supporting cells express GFP which delineates cell shape revealing several cells with thin, basally directed extensions (inset). Scale bar 20 µm. (B) Labelling for SOX2 (red), and B’) SOX2 and GFP expression, 2 days after transduction. Arrows indicate nuclei labelled for SOX2 (B) inside cells that express GFP (B’). Scale bar: 10 µm. (C) Frozen section. Labelling for ATOH1(red) and C’) ATOH1 with GFP expression in utricular macula 5 days after transduction. Arrows indicate nucleus labelled for ATOH1 (C) in cell that expresses GFP (C’). Adjacent cell, with basally directed extension expresses GFP but the nucleus does not label for ATOH1. Scale bar: 10 µm. (D) Frozen section. Labelling for ATOH1(red) and D’) ATOH1 with GFP expression in crista 5 days after transduction. Several cells whose nuclei label for ATOH1 also express GFP, but there are also cells with ATOH1 +nuclei which do not express GFP. Phalloidin-labelled actin, as well as DAPI to label nuclei, is in the blue channel to label the intercellular junctions as orientation for identification of the luminal surface of the epithelium. Scale bar: 10 µm. (E) Myosin VIIa (red) labels cell that also expresses GFP (E’). Adjacent cell, with morphological characteristics of supporting cell, expresses GFP but not Myosin VIIa. Scale bar: 10 µm. (F) 18 days after transduction, many cells label for Myosin VIIa (red). Scale Bar: 20 µm. (G) Myosin VIIa labelling, (G’) GFP expression, (G’’) Merge of myosin VIIA labelling (red) and GFP at 18 days post transduction. Arrows indicate some cells expressing GFP that label for myosin VIIa. The intensity of labelling for myosin VIIa and the level of expression of GFP vary. Myosin VIIa labelled cells often clustered together and appear to be in contact. Scale bar: 10 µm. (H, H’) Some cells at 18 days after transduction that are labelled for myosin VIIa (H) and also express GFP (H’) have thin basally extended projections. Scale bar: 10 µm.