Analysis and Comparison of Partial Sequences of Clones from a Taste-bud-enriched cDNA Library

Abstract

Differential patterns of cellular development and function are determined, at least in part, by the specific gene expression of particular cells. Thus, determination of differential patterns of gene expression between tissues is likely to help elucidate molecular details of tissue-specific processes. Our hypothesis was that cells of the circumvallate papilla involved in taste perception would express genes that are not expressed in the surrounding epithelium and that determination of the nature of these genes could be helpful in our understanding of the molecular details of taste. Using partial sequencing of clones derived from rat circumvallate papillae, we have begun to characterize genes that could be important in taste. We prepared a cDNA library of whole circumvallate papillae and, by means of a novel subtraction procedure, enriched taste-specific clones. Characterization of the libraries showed that subtraction resulted in good enrichment of taste-specific clones. Here we report the partial sequencing and analysis of 410 cDNA clones from the taste-bud-enriched cDNA library. Approximately 25% of the genes were identified on the basis of their high homology to known transcripts. These included the developmentally important molecules Pax-1, espl, Notch 1, and Notch 3 that may play roles in the continuous turnover of taste receptor cells. A further 20% of the genes had no significant homology to known DNA sequences and were identified as taste-specific by Southern blot analysis.