A biochemical function for the Sm complex.
Within the yeast commitment complex, SmB, SmD1, and SmD3 make direct contact with the pre-mRNA substrate, close to the 5' splice site. Only these three Sm proteins have long and highly charged C-terminal tails, in metazoa as well as in yeast. We replaced these proteins with tail-truncated versions. Genetic assays demonstrate that the tails contribute to similar and overlapping functions, and cross-linking assays show that the tails make direct contact with the pre-mRNA in a largely sequence-independent manner. Other biochemical assays indicate that they function at least in part to stabilize the U1 snRNP-pre-mRNA interaction. We speculate that this role may be general, and may have even evolved to aid weak intermolecular nucleic acid interactions of only a few base pairs.
Howard Hughes Medical Institute, Department of Biology, Brandeis University, Waltham, MA 02254, USA.
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Zhang
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Abovich
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Rosbash
D000595:Amino Acid Sequence; D001324:Autoantigens / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D015153:Blotting, Western; D002455:Cell Division; D003432:Cross-Linking Reagents; D005363:Ficusin / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D011233:Precipitin Tests; D015202:Protein Engineering; D017434:Protein Structure, Tertiary; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism*; D012326:RNA Splicing / Q000235:genetics; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017411:Ribonucleoproteins, Small Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017384:Sequence Deletion; D013816:Thermodynamics; D015003:Yeasts / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D055517:snRNP Core Proteins
D001324:Autoantigens; D003432:Cross-Linking Reagents; D005656:Fungal Proteins; D046911:Macromolecular Substances; D012322:RNA Precursors; D016601:RNA-Binding Proteins; D017411:Ribonucleoproteins, Small Nuclear; C091107:SMD3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D055517:snRNP Core Proteins; D005363:Ficusin