Figure 3.

Increasing intron length does not reduce splicing efficiency in-vitro. RNA templates were generated from minigene C and lacked the first seven nucleotides of intron 11. Clong contained an additional 67 nucleotides from the 5' end of intron 10 to maintain intron length at 255 nucleotides (see template A, Fig. 2). Both templates were incubated with 40% HeLa nuclear extract at 0°C or under splicing conditions for 60 min, the RNA extracted and separated on 8% sequencing gels. The RNA templates, spliced RNA (153 nt), and 5' exon (110 nt) are indicated by symbols on the right. Lariat intermediates are indicated by asterisks