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Author(s) -
Miura Hirohito,
Scott Jennifer K.,
Harada Shuitsu,
Barlow Linda A.
Publication year - 2014
Publication title -
developmental dynamics
Language(s) - English
Resource type - Reports
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.24052
Subject(s) - taste bud , biology , sonic hedgehog , microbiology and biotechnology , taste receptor , cell type , taste , mitosis , stem cell , umami , cellular differentiation , cell , progenitor cell , biochemistry , signal transduction , gene
Background: Taste buds contain ∼60 elongate cells and several basal cells. Elongate cells comprise three functional taste cell types: I, glial cells; II, bitter/sweet/umami receptor cells; and III, sour detectors. Although taste cells are continuously renewed, lineage relationships among cell types are ill‐defined. Basal cells have been proposed as taste bud stem cells, a subset of which express Sonic hedgehog ( Shh ). However, Shh + basal cells turn over rapidly suggesting that Shh + cells are post‐mitotic precursors of some or all taste cell types. Results: To fate map Shh ‐expressing cells, mice carrying ShhCreER T2 and a high (CAG‐CAT‐EGFP) or low (R26RLacZ) efficiency reporter allele were given tamoxifen to activate Cre in Shh + cells. Using R26RLacZ, lineage‐labeled cells occur singly within buds, supporting a post‐mitotic state for Shh + cells. Using either reporter, we show that Shh + cells differentiate into all three taste cell types, in proportions reflecting cell type ratios in taste buds (I > II > III). Conclusions: Shh + cells are not stem cells, but are post‐mitotic, immediate precursors of taste cells. Shh + cells differentiate into each of the three taste cell types, and the choice of a specific taste cell fate is regulated to maintain the proper ratio within buds. Developmental Dynamics 243:1286–1297, 2014 . © 2014 Wiley Periodicals, Inc.