Ketola-Pirie CA, Atkinson BG. Thyroid hormone-induced differential synthesis of water-insoluble proteins in epidermal cell cultures from the hind limb of Rana catesbeiana tadpoles in stages XII-XV and XVI-XIX.
Gen Comp Endocrinol 1990;
79:275-82. [PMID:
1697275 DOI:
10.1016/0016-6480(90)90113-z]
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Abstract
Hind limb epidermal cell cultures from stage XII-XV and XVI-XIX tadpoles of the American bullfrog Rana catesbeiana were maintained for 36 and 120 hr in medium containing either fetal calf serum or thyroid hormone (3,3',5-triiodothyronine, T3; 3 x 10(-10) mol/ml). T3 induces the precocious synthesis (within the first 36 hr) of a 59-kDa keratin associated with epidermal stratification in cultures from stages XII-XV. In epidermal cell cultures from stages XVI-XIX, T3 produces an overall pattern of water-insoluble proteins, including keratins, which is strikingly similar to temporally differentiated cultures (120 hr). A 73-kDa protein is among the water-insoluble proteins precociously synthesized by 36-hr-old cultures from stages XVI-XIX treated with T3. This protein, which is not immunoprecipitated by antibodies raised against keratins, corresponds in Mr and pI to a mammalian differentiation-specific desmosomal plaque protein. Immunoprecipitation of keratins from 120-hr-old cultures shows that many of the water-insoluble proteins synthesized are, indeed, keratins. Further, quantitation, by laser densitometry, of immunoprecipitated keratins from 120-hr cultures demonstrates that greater amounts of keratins, particularly the 65 and 59 kDa which are associated with a differentiated epidermis, are present in stages XVI-XIX. This study indicates that epidermal cell cultures from stages XVI-XIX respond more quickly to the differentiating effects of T3.
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