c- myc oncogene protein synthesis is independent of the cell cycle in human and avian cells

Several lines of evidence suggest a role for the myc oncogene in cell proliferation. 1–7 Most recently, mitogenic stimulation of quiescent lymphoid, fibroblast and epithelial cells has been demonstrated to lead to a sharp increase in c- myc RNA levels 8–10 . To determine how c- myc expression is linked to the cell proliferative cycle, we have used centrifugal elutriation to enrich for populations of avian and human cells at different stages of the cell cycle. Centrifugal elutriation is a counterflow centrifugation method that separates cells on the basis of volume, a parameter correlating well with progression through the cell cycle 11–14 . Using myc -specific anti-peptide antibodies, we show here that the synthesis, half-life and modification of c- myc proteins are constant throughout the cell cycle of normal and transformed cells.