Expression of FL mRNA in resting and activated T lymphocytes analyzed by an RNase A/T1 protection assay.
Total RNA was extracted from freshly purified resting cells (control) or following 72 hours culture with anti(α)-CD3 and CD28 mAbs, IL-2 or IL-7 (15 ng/mL each), or IL-7 plus CsA (5 μg/mL). RNA was hybridized with an antisense RNA probe complementary to the region encoding the extracellular part of FL (see “Materials and methods”). After digestion of single-stranded RNA with RNase A and T1, RNA fragments were separated by gel electrophoresis and exposed to x-ray film. Probe/RNase indicates digested probe; probe, nondigested probe. Migration of size markers is indicated. The control reaction was carried out with RNA probe complementary to β-actin mRNA. Arrows mark RNA fragments of the expected sizes 357 nt and 517 nt corresponding to positions 68-585 and 68-435 in the alternatively spliced FL mRNAs.28
