NRF-1 ^NFE2L1 downregulation reduces the expression of some proteasome genes in denervated muscle. (A) shNFE2L1 downregulates NFE2L1 in NIH-3T3 cells. mRNA preparations from cells transfected with shLacz control or shNFE2L1 were analyzed by RT-PCR and specific primers to NFE2L1. Means ± SEM are presented as ratio to shLacz. N = 5 wells of cells per shRNA. *, P < 0.05 versus shLacz by one-tailed paired Student’s t test. (B and C) Expression of proteasome genes (B) and UPS components (C) was measured by RT-PCR analysis of mRNA preparations from innervated and 10-day denervated muscles expressing shNFE2L1 or shLacz. Means ± SEM are presented as a ratio to innervated. N = 4 mice per condition. *, P < 0.05 and **, P < 0.005 versus innervated shLacz; #, P < 0.05 versus denervated shLacz by one-tailed unpaired Student’s t test. (D) Downregulation of NFE2L1 by shNFE2L1 does not attenuate the atrophy of denervated muscles (10 days). Graph depicts mean weights (mg) ± SEM of denervated TA muscles. N = 6 mice per condition. **, P < 0.005 versus innervated shLacz by one-tailed unpaired Student’s t test.