TABLE 1.

Regulation of various genes by dexamethasone

Gene	Synonym(s)	Expression level of gene (arbitrary units)a
		Control	100 nM Dex	1 μM Dex
GAPDH		18,911	20,491	19,537
β-Actin		18,544	19,673	18,732
MT-1A		3,883	6,710	8,508
IκBα		1,726	3,206	3,109
IL-8		527	ND	ND
DUSP1	MKP-1, CL-100, Erp	3,387	6,436	5,951
DUSP2	PAC-1	343	903	879
DUSP4	MKP-2, hVH2	230	389	339
DUSP5	hVH3	324	ND	ND
DUSP10	MKP-5	288	305	356
DUSP11	PIR1	1,960	1,576	1,508
Wip1		685	573	506

^aHeLa-TO cells were treated for 2 h with vehicle (methanol) (control) or with 100 nM or 1 μM dexamethasone (Dex). Total RNA was prepared and analyzed using Affymetrix U95Av2 arrays as described in Materials and Methods. Raw data sets from the chip reader were normalized against one another using the mean expression level of all detected transcripts under each condition. Correction factors applied to the 100 nM and 1,000 nM dexamethasone data sets were 1.156 and 0.99, respectively. Normalization using the GAPDH or β-actin signals gave almost identical results. Normalization using internal control poly(A) mRNAs (added at the cRNA synthesis step) suggested slightly stronger up-regulation of MKP-1 gene expression by 100 and 1,000 nM dexamethasone (2.4- and 2.6-fold rather than 1.7-and 1.5-fold as shown above). An arbitrary cutoff of 200 expression units was employed, and genes expressed below this level were considered not detected (ND).