Transcription of different suptRNA^Trp genes in vitro. (A) This autoradiograph presents a typical experiment, with samples electrophoresed until the bromophenol blue marker was only about halfway down the gel to reduce sample spreading for convenience. (B) Quantitation of transcript labelling for different suptRNA genes. The amount of incorporation into bands excised from gels such as those shown in panel A was quantitated by Cerenkov counting, as indicated in Materials and Methods.