Activated MEK/ERK signalling regulates a portion of genes regulated by TNFα signalling. Total mRNA from two independent experiments of primary chondrocytes pretreated with dimethyl sulfoxide or U0126 for 30 minutes followed by treatment with vehicle or TNFα for 24 hours was subjected to microarray analysis. The number of probe sets changing expression ≥ 1.45-fold in TNFα-treated cells (first bar), and the distribution of those changes that are dependent (second bar) or independent (third bar) of mitogen-activated kinase kinase (MEK) 1/2 activity. Probe sets showing ≥ 1.45-fold fold changes with U0126 treatment alone are indicated by the last bar. In order for a probe set to be counted in these categories, the gene needed to be increased or decreased in the same direction ≥ 1.45-fold in both of the two independent experiments. For each bar, the number of genes downregulated (white) and upregulated (black) are indicated. ERK, extracellular regulated kinase.
Rockel et al. Arthritis Research & Therapy 2009 11:R8 doi:10.1186/ar2595