Topography of the predifferentiation GD growth arrest state relative to other growth arrest states in the G1 phase of the cell cycle

Abstract

The differentiation of 3T3 T proadipocytes is preceded by growth arrest at a state in the G₁ phase of the cell cycle (G_D) which is distinct from other G₁ growth arrest states including those induced by serum deprivation (G_S) or nutrient deprivation (G_N) (Scott et al., 1982). We now report that the G_D, G_S, and G_N arrest states are also distinct in their topography in G₁. This conclusion was derived from kinetic studies which measured the time required for cells arrested at various G₁ states to synthesize DNA and from studies on the ability of G_D‐, G_S‐, or G_N‐arrested cells to be converted from one arrest state to another in the absence of DNA synthesis. The results suggest that relative to the start of the G₁ phase of the cell cycle, the following arrest state topography exists: G_D, G_S, G_N.