The Journal of Neuroscience, June 1, 2002, 22(11):4522-4529
Analysis of Cell Lineage Relationships in Taste Buds
Leslie M.
Stone1, 5,
Seong-Seng
Tan3,
Patrick P. L.
Tam4, and
Thomas E.
Finger2, 5
1 Department of Biomedical Sciences, Colorado State
University, Fort Collins, Colorado 80523, 2 Department of
Cellular and Structural Biology, University of Colorado Health Sciences
Center, Denver, Colorado 80262, 3 Brain Development
Laboratory, Howard Florey Institute, University of Melbourne, Parkville
3010, Australia, 4 Embryology Unit, The Children's Medical
Research Institute, University of Sydney, Wentworthville, New South
Wales 2145, Australia, and 5 Rocky Mountain Taste and Smell
Center, University of Colorado Health Sciences Center, Denver, Colorado
80262
Taste buds are a heterogeneous population of cells exhibiting
diverse morphological and biochemical characteristics. Because taste
buds arise from multiple progenitors, the different types of taste
cells may represent distinct lineages. The present study was undertaken
to determine the following: (1) how many progenitors contribute to a
taste bud, and (2) whether the specific subpopulation of
serotonin-immunoreactive (IR) taste cells are related by lineage to a restricted set of progenitor cells. These questions were addressed
using cell lineage analysis of taste buds from H253 X-inactivation
mosaic mice. After random X-inactivation of the lacZ
transgene, the tongue of hemizygous female mice displays discrete
patches of epithelial cells, which are either 
-galactosidase (-gal) positive or -gal negative. By analyzing the proportion of
the two differently stained cell populations in taste buds located at
the boundary between positive and negative epithelial patches, we can
determine the minimum number of progenitors that may contribute to the
formation of a taste bud. The presence of taste buds containing only
6-12% labeled cells indicates that at least eight progenitors
contribute to an average taste bud of 55 cells, assuming progenitors
contribute equally to the cell population. Cell lineage analysis of
serotonin-IR taste cells in such mixed taste buds suggests that this
subpopulation likely arises from only one to two progenitors and often
is related by lineage. Thus, at least some of the cell types in a taste
bud represent distinct lineages of cells and are not merely phenotypic stages as a cell progresses from a young to a mature state.
Key words:
gustatory; development; basal cell; cell lineage; mosaic
analysis; type III cell; serotonin
Copyright © 2002 Society for Neuroscience 0270-6474/02/22114522-08$05.00/0
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