ISSN:
0002-9106
Schlagwort(e):
Life and Medical Sciences
;
Cell & Developmental Biology
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Medizin
Notizen:
The α and β keratins are found as 10-nm and 3-nm cytoplasmic filaments, respectively. While the a keratins are produced in essentially all vertebrate epithelia (Franke et al.: Exp. Cell Res., 116:429-445, 1978; Sun et ah: Proc. Natl. Acad. Set. USA, 76:2813-2817, 1979), the β keratins have been demonstrated only in specific epithelial tissues of birds and reptiles (Sawyer et ah: In: Biology of the Integument: Vertebrates. J. Bereiter-Hahn, A.G. Matoltsy, and K, S. Richards, eds. Springer-Verlag, Berlin, Vol. 2, pp. 194-238,1986; Land-mann: In: Biology of the Integument: Vertebrates. J. Bereiter-Hahn, A.G. Matoltsy, and K.S. Richards, eds. Springer-Verlag, Berlin, Vol. 2, pp. 150-187, 1986). Recently, Homberger and Brush (Zoomorphology, 106:103-114, 1986) have demonstrated that within the lingual epithelium of parrots, β keratins are expressed exclusively in the anterior ventral region. While it is well established that epidermal-dermal interactions are important for the regional expression of the β keratin genes in the avian scutate scales and feathers, little is known about the expression of β keratins in other epithelial structures such as the tongue. We have used biochemical and immunocytochemical techniques to analyze the a and β keratins of the lingual epithelium of the chick as an initial step in the characterization of this model system for developmental studies. We have found that α keratins are present throughout the lingual epithelium. The anterior ventral epithelium contains α keratin polypeptides characteristic of skin-type differentiation, while the epithelium of the dorsal and posterior ventral regions contains α keratin polypeptides characteristic of esophageal-type differentiation (O'Guin et al.: In: Current Topics in Developmental Biology: The Molecular and Developmental Biology of Keratins. A.A. Moscona and A. Monroy, eds. R.H. Sawyer, vol. ed. Academic Press, New York, Vol. 22, pp. 282-306, 1987). Beta keratins are produced only in the differentiated epithelial cells of the anterior ventral region of the tongue. Immunoelectron microscopy demonstrates that the α and β keratins of the stratum intermedium and corneum of the anterior ventral region are found together in the large filament bundles characteristic of this region. The preexistence of the α keratins in the cells destined to produce β keratins as well as the colocalization of these keratins in the filament bundles of these cells suggests that a functional relationship may exist between the α. and β keratins.
Zusätzliches Material:
12 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/aja.1001840108
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