Reassessing the genetic lineage tracing of lingual and cells .

Taste buds, the neuroepithelial organs responsible for the detection of gustatory stimuli in the oral cavity, arise from stem/progenitor cells among nearby basal keratinocytes. Using genetic lineage tracing, and were suggested as the specific markers for the stem/progenitor cells of taste buds, but recent evidence implied that taste buds may arise even in the absence of these markers. Thus, we wanted to verify the genetic lineage tracing of lingual - and -expressing cells. Unexpectedly, we found that antibody staining revealed more diverse -expressing cells inside and outside the taste buds of circumvallate papillae than was previously suggested. We also found that, while tamoxifen-induced genetic recombination occurred only in cells expressing the reporter GFP, we did not see any increase in the number of recombined daughter cells induced by consecutive injections of tamoxifen. Similarly, we found that cells expressing , another stem/progenitor cell marker candidate and an analog of , also do not generate recombined clones. In contrast, -expressing cells in fungiform papillae can transform into negative progeny. Together, our data indicate that lingual - and -expressing cells exhibit diversity in their capacity to transform into - and -negative cells, depending on their location. Our results complement previous findings that did not distinguish this diversity.