Deregulated c-myc expression overrides IFNγ-induced macrophage growth arrest

Abstract

Induction of c-myc gene expression is an essential response to growth promoting agents, including colony-stimulating factor 1 (CSF-1). Down regulation of c-myc expression occurs in response to a variety of negative growth regulators in many cell types. However, for many of these systems the causal link between c-myc down regulation and growth arrest remains to be established. Here we show for CSF-1-dependent BAC1.2F5 mouse macrophages that interferon-γ (IFNγ) results in a mid-late G1 phase decrease of CSF-1-dependent c-myc mRNA and subsequent cell cycle arrest. Introduction of a deregulated c-myc gene into these cells, which prevents the IFNγ-mediated decrease in c-myc expression, overrides ..