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Keiper S, Papasaikas P, Will CL, Valcárcel J, Girard C, Lührmann R. Smu1 and RED are required for activation of spliceosomal B complexes assembled on short introns. Nat Commun 2019; 10:3639. [PMID: 31409787 PMCID: PMC6692369 DOI: 10.1038/s41467-019-11293-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 07/01/2019] [Indexed: 12/02/2022] Open
Abstract
Human pre-catalytic spliceosomes contain several proteins that associate transiently just prior to spliceosome activation and are absent in yeast, suggesting that this critical step is more complex in higher eukaryotes. We demonstrate via RNAi coupled with RNA-Seq that two of these human-specific proteins, Smu1 and RED, function both as alternative splicing regulators and as general splicing factors and are required predominantly for efficient splicing of short introns. In vitro splicing assays reveal that Smu1 and RED promote spliceosome activation, and are essential for this step when the distance between the pre-mRNA’s 5′ splice site (SS) and branch site (BS) is sufficiently short. This Smu1-RED requirement can be bypassed when the 5′ and 3′ regions of short introns are physically separated. Our observations suggest that Smu1 and RED relieve physical constraints arising from a short 5′SS-BS distance, thereby enabling spliceosomes to overcome structural challenges associated with the splicing of short introns. Human spliceosome components Smu1 and RED regulate alternative splicing. Here the authors show that Smu1 and RED are also required for constitutive splicing of short introns.
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Affiliation(s)
- Sandra Keiper
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Panagiotis Papasaikas
- Centre de Regulació Genòmica, The Barcelona Institute of Science and Technology and Universitat Pompeu Fabra, Dr. Aiguader 88, 08003, Barcelona, Spain.,Friedrich Miescher Institute for Biomedical Research (FMI), Maulbeerstrasse 66, 4058, Basel, Switzerland.,Swiss Institute of Bioinformatics, 4058, Basel, Switzerland
| | - Cindy L Will
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Juan Valcárcel
- Centre de Regulació Genòmica, The Barcelona Institute of Science and Technology and Universitat Pompeu Fabra, Dr. Aiguader 88, 08003, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys, 08010, Barcelona, Spain
| | - Cyrille Girard
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.
| | - Reinhard Lührmann
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.
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Voorbij AMWY, van Steenbeek FG, Vos-Loohuis M, Martens EECP, Hanson-Nilsson JM, van Oost BA, Kooistra HS, Leegwater PA. A contracted DNA repeat in LHX3 intron 5 is associated with aberrant splicing and pituitary dwarfism in German shepherd dogs. PLoS One 2011; 6:e27940. [PMID: 22132174 PMCID: PMC3223203 DOI: 10.1371/journal.pone.0027940] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 10/28/2011] [Indexed: 12/03/2022] Open
Abstract
Dwarfism in German shepherd dogs is due to combined pituitary hormone deficiency of unknown genetic cause. We localized the recessively inherited defect by a genome wide approach to a region on chromosome 9 with a lod score of 9.8. The region contains LHX3, which codes for a transcription factor essential for pituitary development. Dwarfs have a deletion of one of six 7 bp repeats in intron 5 of LHX3, reducing the intron size to 68 bp. One dwarf was compound heterozygous for the deletion and an insertion of an asparagine residue in the DNA-binding homeodomain of LHX3, suggesting involvement of the gene in the disorder. An exon trapping assay indicated that the shortened intron is not spliced efficiently, probably because it is too small. We applied bisulfite conversion of cytosine to uracil in RNA followed by RT-PCR to analyze the splicing products. The aberrantly spliced RNA molecules resulted from either skipping of exon 5 or retention of intron 5. The same splicing defects were observed in cDNA derived from the pituitary of dwarfs. A survey of similarly mutated introns suggests that there is a minimal distance requirement between the splice donor and branch site of 50 nucleotides. In conclusion, a contraction of a DNA repeat in intron 5 of canine LHX3 leads to deficient splicing and is associated with pituitary dwarfism.
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Affiliation(s)
- Annemarie M. W. Y. Voorbij
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Frank G. van Steenbeek
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Manon Vos-Loohuis
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Ellen E. C. P. Martens
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Jeanette M. Hanson-Nilsson
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Bernard A. van Oost
- Department of Biochemistry, American University of the Caribbean, Cupecoy, St. Maarten, Netherlands Antilles
| | - Hans S. Kooistra
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Peter A. Leegwater
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
- * E-mail:
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Liu HX, Goodall GJ, Kole R, Filipowicz W. Effects of secondary structure on pre-mRNA splicing: hairpins sequestering the 5' but not the 3' splice site inhibit intron processing in Nicotiana plumbaginifolia. EMBO J 1995; 14:377-88. [PMID: 7835348 PMCID: PMC398092 DOI: 10.1002/j.1460-2075.1995.tb07012.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We have performed a systematic study of the effect of artificial hairpins on pre-mRNA splicing in protoplasts of a dicot plant, Nicotiana plumbaginifolia. Hairpins with a potential to form 18 or 24 bp stems strongly inhibit splicing when they sequester the 5' splice site or are placed in the middle of short introns. However, similar 24 bp hairpins sequestering the 3' splice site do not prevent this site from being used as an acceptor. Utilization of the stem-located 3' site requires that the base of the stem is separated from the upstream 5' splice site by a minimum of approximately 45 nucleotides and that another 'helper' 3' splice site is present downstream of the stem. The results indicate that the spliceosome or factors associated with it may have a potential to unfold secondary structure present in the downstream portion of the intron, prior to or at the step of the 3' splice site selection. The finding that the helper 3' site is required for utilization of the stem-located acceptor confirms and extends previous observations, obtained with HeLa cell in vitro splicing systems, indicating that the 3' splice site may be recognized at least twice during spliceosome assembly.
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Affiliation(s)
- H X Liu
- Friedrich Miescher-Institut, Basel, Switzerland
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Reich CI, VanHoy RW, Porter GL, Wise JA. Mutations at the 3' splice site can be suppressed by compensatory base changes in U1 snRNA in fission yeast. Cell 1992; 69:1159-69. [PMID: 1617727 DOI: 10.1016/0092-8674(92)90637-r] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
U1 snRNA is an essential splicing factor known to base pair with 5' splice sites of premessenger RNAs. We demonstrate that pairing between the universally conserved CU just downstream from the 5' junction interaction region and the 3' splice site AG contributes to efficient splicing of Schizosaccharomyces pombe introns that typify the AG-dependent class described in mammals. Strains carrying mutations in the 3' AG of an artificial intron accumulate linear precursor, indicative of a first step block. Lariat formation is partially restored in these mutants by compensatory changes in nucleotides C7 and U8 of U1 snRNA. Consistent with a general role in fission yeast splicing, mutations at C7 are lethal, while U8 mutants are growth impaired and accumulate linear, unspliced precursor to U6 snRNA. U1 RNA-mediated recognition of the 3' splice site may have origins in analogous intramolecular interactions in an ancestral self-splicing RNA.
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Affiliation(s)
- C I Reich
- University of Illinois, Department of Biochemistry, Urbana 61801
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