Cis-regulatory elements of alternative splicing in the human FAK gene. Known cis-regulatory elements involved in mRNA alternative splicing were searched in the human FAK gene (NCBI Gene ID: 5747) as described in the Methods section. (A) Frequency of ACE-EXs per 100 bp in each FAK exon. (B) Frequencies of exonic splicing enhancers (ESE, black) and exonic splicing silencers (ESS, grey) per 100 bp in each FAK exon (for example 5 ESE and 23 ESS/100 bp were found in exon 14). (C) Frequency of the hexamer UGCAUG per 10,000 bp in each FAK intron (numbered according to their 5' flanking exon).