Differential induction of 15 and 16 kDa nuclear proteins in promotion sensitive and promotion resistant mouse JB6 cells.
Gene expression relevant to promotion of neoplastic transformation was investigated by measuring proteins differentially synthesized in two mouse epidermal JB6 cell lines sensitive (P+) or resistant (P-) to tumor promoter induced transformation. One dimensional polyacrylamide gel electrophoresis of proteins from cells that had been pulse labeled with 35S-methionine after various times of exposure to the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) revealed two protein bands whose intensity increased after 20-24 hr exposure to TPA. Cell fractionation showed that these proteins of 15 and 16 kDa were localized in the nuclear, not the cytosolic, fraction. Parallel studies with 32P-labeled cells showed no evidence for phosphorylation of these proteins. Comparison of P- with P+ cells showed that the observed induction of p15/16 synthesis at 20 hr was specific for P+ cells, with little evidence for stimulated synthesis in P- cells during a 48 hr period. We thus conclude that the tumor promoter produces a late stimulation in the rate of synthesis of 15 and 16 kDa nuclear proteins preferentially in promotion sensitive cells.
Hirano
K
K
Laboratory of Viral Carcinogenesis, National Cancer Institute, Frederick Cancer Research and Development Center, MD 21702-1201.
Smith
B M
BM
Colburn
N H
NH
D000818:Animals; D002273:Carcinogens; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000187:drug effects* / Q000378:metabolism; D066298:In Vitro Techniques; D051379:Mice; D008970:Molecular Weight; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D002273:Carcinogens; D009687:Nuclear Proteins; D013755:Tetradecanoylphorbol Acetate