Alternative splicing of Alu exons--two arms are better than one.

@article{citeulike:2460794, abstract = {Alus, primate-specific retroelements, are the most abundant repetitive elements in the human genome. They are composed of two related but distinct monomers, left and right arms. Intronic Alu elements may acquire mutations that generate functional splice sites, a process called exonization. Most exonizations occur in right arms of antisense Alu elements, and are alternatively spliced. Here we show that without the left arm, exonization of the right arm shifts from alternative to constitutive splicing. This eliminates the evolutionary conserved isoform and may thus be selected against. We further show that insertion of the left arm downstream of a constitutively spliced non-Alu exon shifts splicing from constitutive to alternative. Although the two arms are highly similar, the left arm is characterized by weaker splicing signals and lower exonic splicing regulatory (ESR) densities. Mutations that improve these potential splice signals activate exonization and shift splicing from the right to the left arm. Collaboration between two or more putative splice signals renders the intronic left arm with a pseudo-exon function. Thus, the dimeric form of the Alu element fortuitously provides it with an evolutionary advantage, allowing enrichment of the primate transcriptome without compromising its original repertoire.}, address = {Department of Human Genetics and Molecular Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel.}, author = {Gal-Mark, Nurit and Schwartz, Schraga and Ast, Gil }, citeulike-article-id = {2460794}, issn = {1362-4962}, journal = {Nucleic Acids Res}, keywords = {alu, exonisation, te}, month = {February}, posted-at = {2008-03-03 12:48:59}, priority = {0}, title = {Alternative splicing of Alu exons--two arms are better than one.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/18276646}, year = {2008} }

TY - JOUR ID - citeulike:2460794 L3 - citeulike-article-id:2460794 TI - Alternative splicing of Alu exons--two arms are better than one. JF - Nucleic Acids Res AD - Department of Human Genetics and Molecular Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel. SN - 1362-4962 N2 - Alus, primate-specific retroelements, are the most abundant repetitive elements in the human genome. They are composed of two related but distinct monomers, left and right arms. Intronic Alu elements may acquire mutations that generate functional splice sites, a process called exonization. Most exonizations occur in right arms of antisense Alu elements, and are alternatively spliced. Here we show that without the left arm, exonization of the right arm shifts from alternative to constitutive splicing. This eliminates the evolutionary conserved isoform and may thus be selected against. We further show that insertion of the left arm downstream of a constitutively spliced non-Alu exon shifts splicing from constitutive to alternative. Although the two arms are highly similar, the left arm is characterized by weaker splicing signals and lower exonic splicing regulatory (ESR) densities. Mutations that improve these potential splice signals activate exonization and shift splicing from the right to the left arm. Collaboration between two or more putative splice signals renders the intronic left arm with a pseudo-exon function. Thus, the dimeric form of the Alu element fortuitously provides it with an evolutionary advantage, allowing enrichment of the primate transcriptome without compromising its original repertoire. KW - alu KW - exonisation KW - te AU - Gal-Mark, Nurit AU - Schwartz, Schraga AU - Ast, Gil PY - 2008/02/14/ UR - http://view.ncbi.nlm.nih.gov/pubmed/18276646 ER -