PMC

Splice variants of polypyrimidine-tract-binding protein.

Distribution of distances between alternative splice sites: (A) 5′-splice sites; (B) 3′-splice sites. Note that we only show the distribution up to a distance of 100 nt.

Estimated frequency of lengths of constitutive (black) and cryptic (red) exons. For each value of the length L we determined the frequency in our data set of exons with length between 0.8 L and 1.2 L.

Position-specific probability that the nucleotides at (A) 5′- and (B) 3′-splice signals of cryptic exons were generated from different versus the same underlying distribution as those of the constitutive exons.

Annotation of variant exons. The splice sites responsible for the annotation of the associated exons as variant are indicated by vertical bars. Exons with invariant splice sites are shown in green, exons with alternative 5′ sites are shown in yellow, and those with alternative 3′ sites in blue. Cryptic exons are indicated by a black box surrounding the exon. Introns are shown in red.

Nucleotide distribution in the (A,C) 5′- and (B,D) 3′-splice signals flanking constitutive (upper panels) and cryptic (lower panels) exons. The relative sizes of the letters indicate the relative frequencies of the nucleotides at that distance from the splice junctions. The absolute sizes of the letters correspond to the information score of the nucleotide distribution at that position.