Time course of GM-CSF mRNA accumulation in BMSCs stimulated with TNF-.

(A) This experiment was similar to the one described in the legend to Figure 2, except that the control cells were derived from an Htz mouse, and were stimulated with TNF-α (10 ng/mL) instead of LPS; 20 μg of total cellular RNA was loaded into each gel lane. The blots for GM-CSF mRNA were exposed to autoradiographic film in the same cassette for 7 days. Note the clear presence of the 2 species of GM-CSF mRNA in the Htz cells, whereas the smaller band was essentially absent in the KO cells. Note also that GM-CSF mRNA was already detectable after 45 minutes in the KO cells, but was not detectable until 1 hour in the Htz cells; in addition, GM-CSF mRNA was detectable for up to 8 hours in the KO cells, whereas the mRNA was not detected after 5 hours in the Htz cells. As in Figure 2, the same blots were then hybridized with a rat GAPDH cDNA probe as a loading control; exposure of the blots to film for GAPDH mRNA was 2 hours. (B) Relative amounts of GM-CSF mRNA after normalization to GAPDH mRNA. Solid symbols, Htz; open symbols, TTP-deficient cells.