BMP4-ß-gal is expressed in a subset of each differentiated taste cell type in circumvallate papillae. Double labeling of BMP4-ß-gal-IR (green nuclei) with differentiated taste cell immunomarkers (red) in circumvallate taste buds. A, A'. Double immunostaining for ß-gal and NTPDase2 (type I cells) reveals double labeled cells (arrowhead in A'). B, B'. In a double immunostained section for BMP4-ß-gal and Gustducin-IR (Type II cells), an arrow indicates one of several cells immunopositive for BMP4-ß-gal but not for gustducin. C, C'. Double staining for BMP4-ß-gal with PLCß2 (type II cells) showing both double labeled (white arrowhead) and singly labeled type II cells (white asterisk). D, D'. Double staining for BMP4-ß-gal with PGP9.5 (subset of type II and III cells) also reveals a double labeled cell (white arrowhead), as well as cells expressing one or the other immunomarker. E, E'. Double staining for BMP4-ß-gal with serotonin-IR (Type III cells) again shows single and double (white arrowhead) labeled taste cells. The boxed area shown in E, is shown in E' as a high magnification view of the merged and channels to better demonstrate double labeling F, F'. Double immunostaining for BMP4-ß-gal with NCAM-IR (type III cells) reveals double (arrowhead) and singly labeled taste cells. A',B',C',D',E', and F' are higher magnification of white boxes in A,B,C,D,E, and F respectively. Scale bars: 20 μm. G: Percentages of type I, II and III taste cells co-expressing BMP4-ß-gal in circumvallate taste buds (mean +/- standard error of the mean, n = 3 mice; 100 to 150 taste buds were counted for each taste cell type marker).