FIGURE 2.

Northern analysis of U7 mutants. (A) (Top) Total RNA extracted from 1- to 2-d-old adult females was fractionated through an 8% polyacrylamide-7 M urea gel, transferred to nitrocellulose, and probed with ³²P-labeled U7 RNA. (Lanes 1–6) RNA from the indicated homozygous mutant genotypes. (Lane 7) w¹¹¹⁸ control RNA. Note the lack of detectable U7 snRNA in the mutant samples. (Bottom) The same blot hybridized with a ³²P-labeled U1 probe as a loading control. (B) Long exposure of mutant samples. The arrow indicates the low abundance, aberrantly large mutant U7 snRNAs produced by the U7²⁰ excision mutant.