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Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
MeSH Review


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Disease relevance of Introns


High impact information on Introns

  • In response to integrin engagement and surface receptor activation, platelets precisely excise introns from interleukin-1beta pre-mRNA, yielding a mature message that is translated into protein [6].
  • The first step in tRNA splicing is the removal of introns catalyzed in yeast by the tRNA splicing endonuclease [7].
  • CDY genes retain CDYL exonic sequences but lack its introns [8].
  • Intron overaccumulation could lead to spliced exon reopening via a reaction known to be catalyzed by group I introns in vitro [9].
  • The telomeric gene is either lacking or interrupted in 226 of 229 patients, and patients retaining this gene (3 of 229) carry either a point mutation (Y272C) or short deletions in the consensus splice sites of introns 6 and 7 [10].

Chemical compound and disease context of Introns


Biological context of Introns

  • Exons become correctly ligated, and the excised intron has a lariat structure similar to that of introns from nuclear mRNA [15].
  • With the exception of two nucleotide substitutions in the large intervening sequence (intron), the intron and flanking sequences are identical with the nucleotide sequence of the first type determined by Weissmann et al [16].
  • Using high-resolution in situ hybridization and computer-aided optical microscope data collection and image analysis, we have determined that the coding portions and introns of the Notch gene, which is not expressed in this tissue, are all contained within the polytene chromosome band 3C7 [17].
  • As in the T4 introns, this open reading frame begins in a region that is looped out of the secondary structure, but ends in a highly conserved region of the intron core [1].
  • Comparison of the in vitro expression of portions of the ovalbumin gene in nuclei isolated from chronically stimulated oviducts indicates that both structural and intervening sequences are preferentially transcribed in vitro at rates approximately 500 times greater than expected for random transcription of the haploid chick genome [18].

Anatomical context of Introns

  • Reverse transcriptase activity associated with maturase-encoding group II introns in yeast mitochondria [19].
  • By studying the processing of model introns in transfected plant protoplasts, we have investigated the special requirements for intron recognition by plant cells [20].
  • The removal of introns from messenger RNA precursors requires five small nuclear RNAs (snRNAs), contained within ribonucleoprotein particles (snRNPs), which complex with the pre-mRNA and other associated factors to form the spliceosome [21].
  • Quantitation of the intron sequences reveals large variations in the amount of both the AChR and actin introns between nuclei within the same myotube, although all nuclei express equivalent amounts of U1 RNA [22].
  • A study was made of the function of the intervening sequences in the ovalbumin gene, Radioactively labeled DNA probes for the intervening sequences were prepared and RNA's were isolated from whole cells, nuclei, and polysomes of estrogen-stimulated chick oviducts [23].

Associations of Introns with chemical compounds

  • Several mutations next to the branch point and in other parts of the core structure of group II introns are shown to affect lariat formation [15].
  • Splicing occurs by the same guanosine-initiated transesterification mechanism characteristic of self-splicing group I introns, but is absolutely dependent upon proteins that are presumably required for correct folding of the pre-rRNA [24].
  • The excised introns of pre-mRNAs and intron-containing splicing intermediates are in a lariat configuration in which the 5' end of the intron is linked by a 2'-5' phosphodiester bond (RNA branch) to a single adenosine residue near the 3' end of the intron [25].
  • The other is a tyrosine tRNA with a 13 bp intervening sequence located immediately adjacent or very close to the 3' nucleotide of the anticodon [26].
  • This structure suggests that introns were not inserted into a previously uninterrupted coding sequence, but instead are products of the evolution of the first pyruvate kinase gene [27].

Gene context of Introns

  • Each of the nine introns in the approximately 6.5 kb rbcL locus is approximately 0.5 kb in length [28].
  • We have isolated seven alleles of PRP16 that, like the original allele prp16-1, allow splicing of introns with a mutant branch site (UACUAAC to UACUACC), by forming lariat intermediates at the mutant C nucleotide [29].
  • Single crossover recombination events between homologous core sequences in the closely linked td and nrdB introns have led to 'exon shuffling [30].
  • Transcripts of COXI and COB genes harboring multiple introns are degraded in the absence of PIM1 [31].
  • The polypyrimidine tract of mammalian introns is recognized by a 62-kD protein (pPTB) [32].

Analytical, diagnostic and therapeutic context of Introns

  • These results are consistent with transcription of the entire ovalbumin gene into a large precursor molecule followed by excision of the intervening sequences and appropriate ligation of the structural sequences to form the mature mRNA [18].
  • Restriction mapping and electron microscopic analyses of this cloned DNA have revealed that the structural ovomucoid gene sequences are separated by at least six intervening sequences [33].
  • To screen the ts- mutants for pre-mRNA splicing defects, an oligodeoxynucleotide that recognizes one of the introns of the beta-tubulin pre-mRNA was used as a probe in a Northern blot assay to detect accumulation of intron sequences [34].
  • The structure and the frequency of the pre-mRNAs of the psbA gene (the gene for the 32-kd protein of photosystem II), which is split by four introns in Euglena chloroplasts was analysed by electron microscopy [35].
  • We also have developed a strategy to identify mutations in COL17A1 by use of PCR amplification of genomic DNA, using primers placed on the flanking introns [36].


  1. A self-splicing group I intron in the DNA polymerase gene of Bacillus subtilis bacteriophage SPO1. Goodrich-Blair, H., Scarlato, V., Gott, J.M., Xu, M.Q., Shub, D.A. Cell (1990) [Pubmed]
  2. Introns in the chicken ovalbumin gene prevent ovalbumin synthesis in E. coli K12. Mercereau-Puijalon, O., Kourilsky, P. Nature (1979) [Pubmed]
  3. Self-splicing introns in tRNA genes of widely divergent bacteria. Reinhold-Hurek, B., Shub, D.A. Nature (1992) [Pubmed]
  4. Group II introns designed to insert into therapeutically relevant DNA target sites in human cells. Guo, H., Karberg, M., Long, M., Jones, J.P., Sullenger, B., Lambowitz, A.M. Science (2000) [Pubmed]
  5. Direct detection of the common Mediterranean beta-thalassemia gene with synthetic DNA probes. An alternative approach for prenatal diagnosis. Orkin, S.H., Markham, A.F., Kazazian, H.H. J. Clin. Invest. (1983) [Pubmed]
  6. Escaping the nuclear confines: signal-dependent pre-mRNA splicing in anucleate platelets. Denis, M.M., Tolley, N.D., Bunting, M., Schwertz, H., Jiang, H., Lindemann, S., Yost, C.C., Rubner, F.J., Albertine, K.H., Swoboda, K.J., Fratto, C.M., Tolley, E., Kraiss, L.W., McIntyre, T.M., Zimmerman, G.A., Weyrich, A.S. Cell (2005) [Pubmed]
  7. Identification of a human endonuclease complex reveals a link between tRNA splicing and pre-mRNA 3' end formation. Paushkin, S.V., Patel, M., Furia, B.S., Peltz, S.W., Trotta, C.R. Cell (2004) [Pubmed]
  8. Retroposition of autosomal mRNA yielded testis-specific gene family on human Y chromosome. Lahn, B.T., Page, D.C. Nat. Genet. (1999) [Pubmed]
  9. The DExH box protein Suv3p is a component of a yeast mitochondrial 3'-to-5' exoribonuclease that suppresses group I intron toxicity. Margossian, S.P., Li, H., Zassenhaus, H.P., Butow, R.A. Cell (1996) [Pubmed]
  10. Identification and characterization of a spinal muscular atrophy-determining gene. Lefebvre, S., Bürglen, L., Reboullet, S., Clermont, O., Burlet, P., Viollet, L., Benichou, B., Cruaud, C., Millasseau, P., Zeviani, M. Cell (1995) [Pubmed]
  11. The quantitation and distribution of splicing intermediates in HeLa cells and adenovirus RNAs. Reilly, J.D., Wallace, J.C., Edmonds, M. Nucleic Acids Res. (1987) [Pubmed]
  12. Genomic and evolutionary analysis of Feilai, a diverse family of highly reiterated SINEs in the yellow fever mosquito, Aedes aegypti. Tu, Z. Mol. Biol. Evol. (1999) [Pubmed]
  13. A novel RNA motif for neomycin recognition. Wallis, M.G., von Ahsen, U., Schroeder, R., Famulok, M. Chem. Biol. (1995) [Pubmed]
  14. Gene organization of a Plasmodium falciparum serine hydroxymethyltransferase and its functional expression in Escherichia coli. Alfadhli, S., Rathod, P.K. Mol. Biochem. Parasitol. (2000) [Pubmed]
  15. Self-splicing of group II introns in vitro: mapping of the branch point and mutational inhibition of lariat formation. Schmelzer, C., Schweyen, R.J. Cell (1986) [Pubmed]
  16. The structure and transcription of four linked rabbit beta-like globin genes. Hardison, R.C., Butler, E.T., Lacy, E., Maniatis, T., Rosenthal, N., Efstratiadis, A. Cell (1979) [Pubmed]
  17. Precise determination of the molecular limits of a polytene chromosome band: regulatory sequences for the Notch gene are in the interband. Rykowski, M.C., Parmelee, S.J., Agard, D.A., Sedat, J.W. Cell (1988) [Pubmed]
  18. Transcription of structural and intervening sequences in the ovalbumin gene and identification of potential ovalbumin mRNA precursors. Roop, D.R., Nordstrom, J.L., Tsai, S.Y., Tsai, M.J., O'Malley, B.W. Cell (1978) [Pubmed]
  19. Reverse transcriptase activity associated with maturase-encoding group II introns in yeast mitochondria. Kennell, J.C., Moran, J.V., Perlman, P.S., Butow, R.A., Lambowitz, A.M. Cell (1993) [Pubmed]
  20. The AU-rich sequences present in the introns of plant nuclear pre-mRNAs are required for splicing. Goodall, G.J., Filipowicz, W. Cell (1989) [Pubmed]
  21. Human U2 snRNA can function in pre-mRNA splicing in yeast. Shuster, E.O., Guthrie, C. Nature (1990) [Pubmed]
  22. Localization of an acetylcholine receptor intron to the nuclear membrane. Berman, S.A., Bursztajn, S., Bowen, B., Gilbert, W. Science (1990) [Pubmed]
  23. Distribution of RNA transcripts from structural and intervening sequences of the ovalbumin gene. Tsai, M.J., Tsai, S.Y., O'Malley, B.W. Science (1979) [Pubmed]
  24. Protein-dependent splicing of a group I intron in ribonucleoprotein particles and soluble fractions. Garriga, G., Lambowitz, A.M. Cell (1986) [Pubmed]
  25. Cryptic branch point activation allows accurate in vitro splicing of human beta-globin intron mutants. Ruskin, B., Greene, J.M., Green, M.R. Cell (1985) [Pubmed]
  26. Nucleotide sequence of genes coding for tRNAPhe and tRNATyr from a repeating unit of X. laevis DNA. Müller, F., Clarkson, S.G. Cell (1980) [Pubmed]
  27. Intron/exon structure of the chicken pyruvate kinase gene. Lonberg, N., Gilbert, W. Cell (1985) [Pubmed]
  28. Nine introns with conserved boundary sequences in the Euglena gracilis chloroplast ribulose-1,5-bisphosphate carboxylase gene. Koller, B., Gingrich, J.C., Stiegler, G.L., Farley, M.A., Delius, H., Hallick, R.B. Cell (1984) [Pubmed]
  29. A mechanism to enhance mRNA splicing fidelity: the RNA-dependent ATPase Prp16 governs usage of a discard pathway for aberrant lariat intermediates. Burgess, S.M., Guthrie, C. Cell (1993) [Pubmed]
  30. Spontaneous shuffling of domains between introns of phage T4. Bryk, M., Belfort, M. Nature (1990) [Pubmed]
  31. The ATP-dependent PIM1 protease is required for the expression of intron-containing genes in mitochondria. van Dyck, L., Neupert, W., Langer, T. Genes Dev. (1998) [Pubmed]
  32. Characterization of cDNAs encoding the polypyrimidine tract-binding protein. Gil, A., Sharp, P.A., Jamison, S.F., Garcia-Blanco, M.A. Genes Dev. (1991) [Pubmed]
  33. The chick ovomucoid gene contains at least six intervening sequences. Catterall, J.F., Stein, J.P., Lai, E.C., Woo, S.L., Dugaiczyk, A., Mace, M.L., Means, A.R., O'Malley, B.W. Nature (1979) [Pubmed]
  34. Pre-mRNA splicing mutants of Schizosaccharomyces pombe. Potashkin, J., Li, R., Frendewey, D. EMBO J. (1989) [Pubmed]
  35. The structure of precursor mRNAs and of excised intron RNAs in chloroplasts of Euglena gracilis. Koller, B., Clarke, J., Delius, H. EMBO J. (1985) [Pubmed]
  36. Cloning of the human type XVII collagen gene (COL17A1), and detection of novel mutations in generalized atrophic benign epidermolysis bullosa. Gatalica, B., Pulkkinen, L., Li, K., Kuokkanen, K., Ryynänen, M., McGrath, J.A., Uitto, J. Am. J. Hum. Genet. (1997) [Pubmed]
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