Figure 1.

(A) Northern blot analysis of p48 gene expression in RAW cells. Poly(A)⁺ RNA (1.5 μg) from IFN-γ-treated cells (1000 units/ml for 18 h) was hybridized with a ³²P-labeled human p48 cDNA (4).The same blot was probed with a labeled human β-actin to ensure the presence of equal amount RNA in each lane. Blots were exposed for 24 and 6 h to detect p48 and β-actin mRNAs, respectively. Where indicated, cells were treated with cycloheximide for 30 min before the addition of IFN-γ. (B) Nuclear runoff transcription. Cells were treated with indicated agents as in A except that IFN-γ treatment was performed for 8 h, and runoff transcription assays, in the presence of [α-³²P]UTP, were performed as described elsewhere. Labeled RNAs were hybridized to indicated cDNAs immobilized on nylon filters. Bluescript and human GAPDH (glyceraldehyde-phosphate dehydrogenase) were used as negative and positive controls for transcription, respectively. (C) Induction of p48 mRNA in mutant cell lines. 2fTGH, U3A, U3AR, U4A, and U4AR cell lines were treated with human IFN-γ (1000 units/ml). Total RNA (40 μg) was Northern blotted and probed as above. C, no treatment; γ, IFN-γ.