FIG. 3.

SCF and Rac2 regulate expression of MMCP-7 gene at the transcriptional level. (A) Nuclear run-on analyses. ³²P-labeled nuclear run-on transcripts from C57BL/6 BMMCs (6-week-old cultures) were used to hybridize to 5 μg of gene-specific DNA probes for MMCP-7, β-actin, and vector only on the membrane. The hybridization intensity is represented in arbitrary units. Wild-type (WT) and Rac2^−/− cells were stimulated with 10 ng of SCF per ml for 1 h. (B) RNA stability analysis. C57BL/6 BMMCs from 6-week-old cultures were stimulated with 10 ng of SCF per ml for 4 h. The cells were then treated with actinomycin D at a final concentration of 1 μg/ml and further cultured with or without SCF. Total RNA was isolated at 0, 1, 5 and 10 h after the addition of actinomycin D. We used 10 μg of total RNA sample for Northern blot analysis examining MMCP-7 transcript levels in the upper panel. The ethidium bromide-stained 28S and 18S RNAs were used as a loading control in the middle panel. The remaining levels of the MMCP-7 transcript are shown in the bottom panel as a percentage of the starting level of the transcript. The result shown is representative of three experiments.