C-FOS TRANSREPRESSION REVISITED

The c-fos proto-oncogene was discovered by homology to transforming vi ral genes, leading to speculation that transforming viruses had captur ed a cellular gene involved in cell cycle control. Indeed overexpressi on of c-Fos protein led to, deregulated growth control, and c-Fos was thought to be so critically involved in cell cycle control that transc riptional transrepression of its own promoter was interpreted as a neg ative feedback mechanism. However, recent findings render this conclus ion improbable, Fos transrepression being most parsimoniously explaine d as transcriptional squelching imposed by artificially elevated level s of exogenous Fos protein.