Multiple splicing signals control alternative intron retention of bovine growth hormone pre-mRNA.
A fraction of bovine growth hormone (bGH) pre-mRNA undergoes alternative splicing in which the last intron is retained and transported to the cytoplasm. Our goal was to characterize the cis-acting signals in bGH pre-mRNA that collectively determine the distribution between intron splicing and intron retention. We now demonstrate that the balance between splicing and intron retention in cytoplasmic mRNA is primarily determined by the interaction of three splicing signals and the degree to which these signals deviate from consensus splicing signals. Intron retention requires the presence of both suboptimal 5'- and 3'-splice sites. Mutation of either splice site toward consensus leads to complete splicing of the intron. In the presence of both wild-type, suboptimal splice sites, efficient splicing of this intron is ensured by the presence of a third splicing element, a purine-rich exonic splicing enhancer (ESE). Although strong ESEs can be contained within very small sequences, the bGH ESE activity appears to be composed of multiple sequences spread throughout a 115-nucleotide region of exon 5. Consequently, the final ratio of splicing to intron retention depends on the balance between the relative strengths of each of these three splicing signals, which still allow intron-containing coding sequences to be transported to the cytoplasm.
Dirksen
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WP
Department of Molecular Biology and Microbiology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106-4960.
Sun
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Rottman
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FM
D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D002417:Cattle; D016384:Consensus Sequence; D006224:Cricetinae; D005091:Exons; D013006:Growth Hormone / Q000096:biosynthesis*; D006367:HeLa Cells; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D012322:RNA Precursors / Q000378:metabolism*; D012326:RNA Splicing; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D015719:Single-Strand Specific DNA and RNA Endonucleases; D014162:Transfection
D012322:RNA Precursors; D012333:RNA, Messenger; D011994:Recombinant Proteins; D013006:Growth Hormone; D015719:Single-Strand Specific DNA and RNA Endonucleases