Upregulation of TNF-α and TGF-β expression by pressure overload is impaired in MEKK1^–/– mice. MEKK1^+/+ (control) and MEKK1^–/– mice were subjected to either aortic banding or sham operation. After 7 days of pressure overload, animals were sacrificed and total RNA was isolated from the apex. mRNA expression of TNF-α and TGF-β was determined by RT-PCR. Expression of GAPDH was determined as an internal control. Representative ethidium bromide staining of the products of RT-PCR is shown. n = 5.