Figure 1.

Time courses of CSF-1–stimulated transcription of c-myc, cyclin D1, and cyclin D2 genes in BAC1.2F5 macrophages. G1-arrested BAC1.2F5 cells were either unstimulated or stimulated with mouse CSF-1 (4.4 nM) at 37°C for the indicated times. In certain experiments (E–H), cells were preincubated with cycloheximide (10 μM) for 20 min before addition of CSF-1. Total RNA was isolated and analyzed for expression of the indicated genes by Northern blotting (30 μg RNA/lane) by using ³²P-labeled c-myc, D1, and D2 cDNA probes. Expression of GAPDH gene was included as control for RNA sample loading. The time of CSF-1 stimulation: E, 45 min; F and G, 5 h. Framing of C and G emphasize the subsequent focus on D2.