Up-regulation of TNFR1 mRNA expression in gut tissue following delayed bortezomib administration. B6 (H2^b) recipients of BALB/c (H2^d) 15 million bone marrow and 20 million spleen cells were treated with or without 15 μg bortezomib per dose daily from day +12 through +13. Small intestine and liver were collected at 6 hours after bortezomib administration (day +13) for RNA extraction. TNFR1 mRNA expression was analyzed by RPA. (A-B) Autoradiograph of TNFR1 and GAPDH bands from gut (A) and liver (B) RPA gels. (C) Quantitative levels of TNFR1 steady-state mRNA levels in the gut and liver tissue from bortezomib and vehicle control-treated animals. Quantitative levels of TNFR1 mRNA were determined by densitometric analysis and are expressed as a ratio of the band volumes of TNFR1 normalized to the GAPDH housekeeping gene. These data are representative of 2 (liver) and 4 (gut) independent experiments. NS indicates not statistically significant.