Fig. 1.

MafK is an immediate early gene upregulated by NGF in PC12 cells. A, B, Time dependence of effect of NGF on MafK mRNA levels in PC12 cells. A, PC12 cells were treated with NGF for the indicated times, and then total RNA was isolated and converted to cDNA by RT-PCR. Semiquantitative PCRs were performed with 25 cycles for MafK and 20 cycles for GAPDH.B, RT reactions were subjected to quantitative real-time PCR. The relative abundances of MafK transcripts were measured as described in Materials and Methods and were normalized to GAPDH mRNA. Data represent mean values, and error bars indicate SE for measurements from four independent experiments. C, MafK mRNA and protein levels in PC12 cells before and after 9 d of NGF treatment. Cells were harvested, and total RNA or total protein was isolated and subjected to RT-PCR (top 2 panels) or immunoblotting (bottom 2 panels), respectively. Immunoblots were coprobed with MafK and ERK antisera. Comparable results were achieved in three independent experiments. D, E, Effect of the protein synthesis inhibitor anisomycin on regulation of MafK mRNA by NGF. PC12 cells were treated for 1 hr with NGF, and total RNA was isolated and subjected to the RT reaction. Anisomycin (A; 10 μm), when used, was added to cultures 1 hr before NGF. Semiquantitative (D) and quantitative real-time (E) PCRs were performed. Sample wcontained water instead of the RT reaction. Data in Erepresent mean values, and error bars indicate SE for measurements from four independent experiments. c, Control, no additive.