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. 1998 Jun;9(6):1523–1536. doi: 10.1091/mbc.9.6.1523

Figure 2.

Figure 2

Polymerase I transcripts. (A) Inhibitors affect incorporation (measured as in Figure 1B, using 2.5 μM UTP and no RNase treatment). Curve 1: no inhibitors added. Curve 2: 200 μg/ml α-amanitin (polymerases II + III inhibited). Curve 3: cells grown in actinomycin D (0.2 μg/ml; 15 min) before lysis, extension in 200 μg/ml α-amanitin (polymerases I, II, + III inhibited). (B) Autoradiographs of gels containing [32P]RNA from panel A. NTs: length in nucleotides. Lanes 1–4. Cells grown in actinomycin D (act D; 0.2 μg/ml; 15 min) before lysis, RNase treatment, and extension (5 min) in 0.225, 0.375, 0.625, or 1.125 μM UTP. Lanes 5–8. After RNase treatment, transcripts were extended (5 min) in 200 μg/ml α-amanitin (am) and 0.125, 0.225, 0.375 or 0.625 μM UTP; longer exposure than lanes 1–4. (C) The relationship between transcript length (number average in nucleotides) and the number of nucleotides (NTs) incorporated (from panels A and B).