Figure 2.

In vitro transcription of SNR6–SPIN alleles. Transcription in yeast subcellular extract was carried out as described in Materials and Methods using 100 ng of plasmid DNA per reaction, and the products were resolved on a denaturing polyacrylamide gel. Positions of U6 RNA, pre-U6 RNA and downstream transcripts are indicated on the left. The presence (+) or absence (−) of the intact SNR6 downstream B block and the S.pombe U6 RNA gene intron (SPIN) is indicated above each lane. Lane 1 contains the products of a reaction with no added plasmid DNA. The following plasmids were used: lane 2, pUC118; lane 3, p-539H6; lane 4, pCCs6; lane 5, pEP6; lane 6, pCCs6-SPIN; lane 7, pEP6-SPIN. Lane 8 contains ³²P-labeled MspI cut pBR322 markers. The size of the markers (in nucleotides) is indicated on the right.