text: Northern and Western blot analyses.
  RNA isolation and Northern blot analysis was performed as previously described (29). In brief, 10 mug of total RNA was loaded per lane and transferred to positively charged nylon membranes (Hybond-N+; GE Healthcare), which was confirmed by ethidium bromide staining of ribosomal RNA species on the membrane. Membranes were hybridized with 1 ng/ml alpha-[32P]dCTP-labeled trichloroacetic acid precipitable probe in ExpressHyb hybridization buffer (Clontech Laboratories, Inc.). All cDNA probes were confirmed to have the appropriate single-copy specificity under these conditions using genomic Southern blot analysis. Band intensities were acquired by phosphorimaging analysis. 
  For Western analysis, whole-cell protein lysates were obtained from CD8+ T cells at the time points indicated in the figures during clonal expansion in 100 U/ml IL-2 with lysis buffer (50 mM Tris [pH 7.5], 150 mM NaCl, 10% glycerol, 5 mM EDTA, 1% NP-40) by resuspending samples in 10 mul per 106 cells and incubating on ice for 30 min in the presence of protease inhibitors. Immunoblot analysis was performed with the antibodies indicated in the figures after SDS-PAGE (10-30 mug of total protein was loaded per well). Quantification of detected protein was performed with an Intelligent Dark Box unit (LAS-3000; Fujifilm) and normalized for loading with the amount of RNA Pol-II detected in each lane. 
  