title: Characteristics of 30-, 63-, and 89-kilodalton proteins whose secretion from mouse fibroblasts is altered by beta-interferon.
abstract: Quiescent mouse BALB/c-3T3 cells were treated with beta-interferon to induce the secretion of proteins of 30 and 89 kDa and with a platelet-derived growth factor preparation to induce the secretion of a 63-kDa protein. To label the secreted proteins the cultures were supplemented with [35S]methionine after addition of the inducer. The proteins in the culture fluid were fractionated resulting in a radioactively pure 63-kDa protein and 30- and 89-kDa protein preparations with residual minor radioactive impurities. The secreted 89-kDa protein shared at least one characteristic with some interferon-induced cell-associated enzymes: it bound double-stranded RNA tightly. The 63-kDa protein was undetectable in the culture fluid from resting BALB/c-3T3 cells and was barely or not at all detectable in the culture fluids from growing BALB/c-3T3 and NIH 3T3 cells, respectively. The protein was, however, among the three major constitutively secreted proteins in the case of growing Kirsten murine sarcoma virus-transformed NIH 3T3 cells. Treatment with 1000 units/ml beta-interferon decreased the accumulation of the 63-kDa protein in the culture fluid of quiescent BALB/c-3T3 cells which had been treated with a platelet-derived growth factor preparation by over 80% and that in the culture fluid of Kirsten murine sarcoma virus-transformed NIH 3T3 cells by about 50%. This decrease was not a consequence of an inhibition of cell growth.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D007370:Interferon Type I / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D011506:Proteins / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D003470:Culture Media; D007370:Interferon Type I; D011506:Proteins