title: Keratin 18 is associated with a subset of older taste cells in the rat.
abstract: All or nearly all intragemmal (elongated) cells of rat taste buds were immunopositive for keratins 7, 8, and 19. In contrast, keratin 18 was detected in 19 +/- 5 cells per taste bud (mean +/- sd), or about 25% of the intragemmal cells. During taste bud development keratins 7, 8, and 19 were evident initially in polygonal cells and later in elongated taste cells. Keratin 8 appeared in vallate taste cells at P0 (postnatal day 0), followed by keratins 7 and 19 at P1, and keratin 18 at P2-P3. Keratin 18 was always limited to elongated cells. The assemblage of elongated taste cells comprising a taste bud began with a single elongated cell, rather than with the synchronous elongation of a cluster of cells. Developmental errors were observed at P2-P3, e.g., some vallate taste cells had a misoriented axis. In order to study the pace of keratin differentiation during cell turnover we injected bromodeoxyuridine (BrdU) into adult rats to monitor taste cell age. Keratin-19-positive intragemmal cells differentiated within 1 day. In contrast, keratin 18 was first detected in cells aged 3 days. Hence, both in taste cell development and replacement, keratin 18 was restricted to the older cells; it was the last taste cell keratin to become expressed during differentiation.
authors.affiliation: Department of Biology, University of Michigan, Ann Arbor 48109, USA.
authors.forename: C
authors.initials: C
authors.lastname: Zhang
authors.forename: M
authors.initials: M
authors.lastname: Cotter
authors.forename: A
authors.initials: A
authors.lastname: Lawton
authors.forename: B
authors.initials: B
authors.lastname: Oakley
authors.forename: L
authors.initials: L
authors.lastname: Wong
authors.forename: Q
authors.initials: Q
authors.lastname: Zeng
mesh_terms: D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D007633:Keratins / Q000032:analysis* / Q000276:immunology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013650:Taste Buds / Q000737:chemistry* / Q000166:cytology
chemical_list: D007633:Keratins; D001973:Bromodeoxyuridine