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.
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.
Department of Zoology, University of Western Ontario, London, Canada.
C A
CA
Ketola-Pirie
B G
BG
Atkinson
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D015180:Electrophoresis, Gel, Two-Dimensional; D000078404:Epidermal Cells; D004817:Epidermis / Q000187:drug effects / Q000378:metabolism*; D006614:Hindlimb; D007163:Immunosorbent Techniques; D007633:Keratins / Q000096:biosynthesis* / Q000302:isolation & purification; D007814:Larva / Q000378:metabolism; D008970:Molecular Weight; D014176:Protein Biosynthesis; D011506:Proteins / Q000302:isolation & purification; D011892:Rana catesbeiana / Q000254:growth & development / Q000378:metabolism*; D012995:Solubility; D013997:Time Factors; D014284:Triiodothyronine / Q000494:pharmacology*; D014867:Water
D011506:Proteins; D014867:Water; D014284:Triiodothyronine; D007633:Keratins