DEVELOPMENTAL-CHANGES IN PROTEIN PROFILE OF CORNIFYING LINGUAL EPITHELIUM

[摘要] Epithelia from the tongue dorsum of 14-21 day embryos, 3 wk old, and adult rats were separated from their connective tissues by incubation in balanced salt solution containing EDTA. Aliquots from total extracts of these tissues were electrophoresed on sodium dodecyl sulfate-polyacrylamide gels. Scans of gels stained with fast green (FG) revealed more than 20 peaks. Ten major peaks ranging from apparent MW of 120,000 to 14,000 daltons comprised about 70% of the total protein on each gel. This report focuses primarily on 2 pairs of peaks, arbitrarily numbered 2 and 3 (MW 71,000 and 69,000) and 9 and 10 (MW 17,500 and 14,000). Peaks 9 and 10 predominated in the 15 day embryos where they comprised about 30% of the total protein. As development proceeded, there was a gradual shift in the protein profile in favor of peaks 2 and 3 until on the 20th day the relative amounts of these peaks reached a maximum and peaks 9 and 10 decreased in relative amounts. The protein profile on the 20th fetal day resembled that of the 3 wk old rats and the adults. The rise in the relative amounts of peaks 2 and 3 coincided with the morphologic appearance of large numbers of tonofilaments and the onset of cornification. When the gel was stained by a procedure specific for sulfhydryl groups, peaks 9 and 10 were especially reactive after the 18th day; planimetric analysis revealed that these had twice the relative affinity for this stain than for FG whereas other peaks had equal or less affinity. The incorporation of [3H]cystine into peaks 9 and 10 was relatively greater than into the other proteins.