New analytical tool for analysis of splice site sequence determinants

A new analytical method has been used to examine the set of40 exon/intron boundaries within the rat embryonic myosin heavychain (MHC_emb) gene. It has also been applied to an additionalset of 850 splice sequences selected from GenBank. Strong evidenceis obtained for the involvement of 3' ends but not 5' ends ofexon sequences in splice site recognition. It can be determinedthat signal sequences of 5' intron ends concentrate near thesplice borders, while the distributions of the 3' intron endshave a diffuse character. The possibility of re-interpretingsome known features, in terms of the absence of certain elementsrather than the presence of elements forming sequence determinants,is discussed. The analysis undertaken enabled us to work outa more detailed set of recognition sequence requirements forthe splicing of nuclear pre-mRNA. In addition to requirementswhich have already been established we suggest the following:the ‘AG-absence’ in the immediate 3' terminal intronsequences; and a minimal match between a particular sequenceand the known exon/intron consensus sequence of 5' splice junctions. Received on March 22, 1988; accepted on November 19, 1988