Fig 1.
A-D: Single-plane laser-scanning confocal photomicrographs illustrate the distribution of RFP+ cells in mature taste buds in young adult (8 week) P0-Cre/RFP mice.
Taste bud cells in lingual fungiform (A), foliate (B), circumvallate (C) papillae and soft palate (D) were labeled by immunoreactivity of a pan-taste cell marker Keratin 8 (Krt8, green). Tissue sections were counterstained with DAPI (blue) to stain the nuclei of all cells. White dotted lines demarcate the epithelium from underlying connective tissue with short arrows pointing to connective tissue. Green dots in A and D bracket taste buds. P0-Cre driven RFP+ cells were abundantly distributed in taste buds and underlying lamina propria of the tongue and soft palate. No RFP+ cells were seen in the surrounding epithelium (arrowheads) of taste buds. Scale bars: 20 μm for all images. E: Histogram shows the average (x̄±SD, n = 3) of RFP+Krt8+ as a proportion of total Krt8+ taste bud cell profiles in fungiform, foliate and circumvallate papillae in 8-week-old mice. F: Data from 3 mice for each stage (2, 4, 8 and 16 week) are represented as box plot of median±percentile. The diamond within each box represents the average (n = 3) of RFP+Krt8+ double labeled versus total Krt8+ taste bud cell profiles in fungiform papillae at different stages.
Fig 2.
P0-Cre labeled type I, II, III taste bud cells.
In lingual and palatal taste buds of adult P0-Cre/RFP mice, RFP+ signals were co-localized with markers for specific taste cell types (white arrowheads), i.e., NTPDaseII for type I cells (A), α-Gustducin for type II cells (B) and SNAP25 for type III cells (C). White dotted lines demarcate the epithelium from underlying connective tissue. Scale bar: 20 μm for all images (single plane laser-scanning confocal).
Table 1.
Proportion of P0-Cre/RFP labeled specific type (I, II, III)of taste bud cell profiles.
Fig 3.
Dermo1-Cre labeled abundant population of taste bud cells.
In adult Dermo1-Cre/RFP mice, RFP+ cells were abundantly distributed in mature taste buds labeled by Krt8 (green) and extensive in the underlying connective tissue of lingual fungiform (A), foliate (B), circumvallate (C) papillae and soft palate (D). Sections were counterstained with DAPI (blue). White dotted lines demarcate the epithelium from underlying connective tissue with arrows pointing to the connective tissue. Green dotted circles outline Fungiform and Soft palate taste buds. Arrowheads in A point to the unlabeled RFP− epithelial cells outside of the taste bud. Scale bar: 20 μm for all images (single plane laser-scanning confocal).
Fig 4.
Dermo1-Cre labeled all three types (I, II, III) of taste bud cells in adult mice.
RFP+ signals were co-localized with markers for specific taste cell types (white arrowheads), i.e., NTPDaseII for type I cells, α-Gustducin for type II cells and SNAP25 for type III cells in the lingual (A, B, C) and palatal (D) taste buds. White dotted lines demarcate the epithelium from underlying connective tissue. Scale bar: 20 μm for all images (single plane laser-scanning confocal).
Fig 5.
Derivation of taste bud cells from Vimentin-expressing cells in the underlying connective tissue.
A, B: In adult wild type mice, the immunoreactivity of Vimentin (Vim, green) was extensively distributed in the tongue connective tissue but not in the epithelium or Krt8+ taste bud cells (red in A). A subpopulation of Vimentin+ cells were also labeled with proliferating cell marker Ki67 (red in B, arrowheads). C: In adult Vimentin-CreER/mGFP mouse, tamoxifen induced mGFP+ cells were seen within the Krt8 (red) labeled taste buds in fungiform and circumvallate papillae in addition to the extensive distribution of mGFP+ cells in the underlying connective tissue. White dots demarcate the border between epithelium and lamina propria with arrows pointing to the connective tissues. Red dotted lines in A and C encircle the taste buds. Arrowheads in C (Fungiform) point to the unlabeled mGFP− epithelial cells. Scale bars: 20 μm for all images (fluorescent light microphotographs in A and single plane confocal images in B and C).