A role for SNU66 in maintaining 5′ splice site identity during spliceosome assembly

(A) Pictograms of the consensus sequence for the first seven nucleotides of the introns. The top is for 185,352 wt C. elegans introns. Below that, arranged in pairs, are the intron starts for the alternative 5′ss whose usage is promoted or reduced for the SNU-66 and SNRP-27 mutant strains. Strains and number of events analyzed are listed. Sequence logos were generated using WebLogo (Crooks et al. 2004). (B) Histogram showing the distance of alternative 5′ss whose usage is increased in each mutant strain relative to the position of the alternative 5′ss whose usage is decreased.