This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Grabowski, P J Articles by Burch, R Search for Related Content PubMed PubMed Citation Articles by Grabowski, P J Articles by Burch, R

Combinatorial splicing of exon pairs by two-site binding of U1 small nuclear ribonucleoprotein particle.

Section of Biochemistry, Brown University, Providence, Rhode Island 02912.

ABSTRACT

A two-site model for the binding of U1 small nuclear ribonucleoprotein particle (U1 snRNP) was tested in order to understand how exon partners are selected in complex pre-mRNAs containing alternative exons. In this model, it is proposed that two U1 snRNPs define a functional unit of splicing by base pairing to the 3' boundary of the downstream exon as well as the 5' boundary of the intron to be spliced. Three-exon substrates contained the alternatively spliced exon 4 (E4) region of the preprotachykinin gene. Combined 5' splice site mutations at neighboring exons demonstrate that weakened binding of U1 snRNP at the downstream site and improved U1 snRNP binding at the upstream site result in the failure to rescue splicing of the intron between the mutations. These results indicate the stringency of the requirement for binding a second U1 snRNP to the downstream 5' splice site for these substrates as opposed to an alternative model in which a certain threshold level of U1 snRNP can be provided at either site. Further support for the two-site model is provided by single-site mutations in the 5' splice site of the third exon, E5, that weaken base complementarity to U1 RNA. These mutations block E5 branchpoint formation and, surprisingly, generate novel branchpoints that are specified chiefly by their proximity to a cryptic 5' splice site located at the 3' terminus of the pre-mRNA. The experiments shown here demonstrate a true stimulation of 3' splice site activity by the downstream binding of U1 snRNP and suggest a possible mechanism by which combinatorial patterns of exon selection are achieved for alternatively spliced pre-mRNAs.

This article has been cited by other articles:

• Romano, M., Marcucci, R., Baralle, F. E. (2001). Splicing of constitutive upstream introns is essential for the recognition of intra-exonic suboptimal splice sites in the thrombopoietin gene. Nucleic Acids Res 29: 886-894 [Abstract] [Full Text]  
• Schaal, T. D., Maniatis, T. (1999). Multiple Distinct Splicing Enhancers in the Protein-Coding Sequences of a Constitutively Spliced Pre-mRNA. Mol. Cell. Biol. 19: 261-273 [Abstract] [Full Text]  
• Hodges, D., Cripps, R. M., O'Connor, M. E., Bernstein, S. I. (1999). The Role of Evolutionarily Conserved Sequences in Alternative Splicing at the 3' End of Drosophila melanogaster Myosin Heavy Chain RNA. Genetics 151: 263-276 [Abstract] [Full Text]  
• Yi, Y., Jack, T. (1998). An Intragenic Suppressor of the Arabidopsis Floral Organ Identity Mutant apetala3-1 Functions by Suppressing Defects in Splicing. Plant Cell 10: 1465-1478 [Abstract] [Full Text]  
• Dirksen, W. P., Sun, Q., Rottman, F. M. (1995). Multiple Splicing Signals Control Alternative Intron Retention of Bovine Growth Hormone Pre-mRNA. J. Biol. Chem. 270: 5346-5352 [Abstract] [Full Text]  
• Côté, J., Beaudoin, J., Tacke, R., Chabot, B. (1995). The U1 Small Nuclear Ribonucleoprotein/5` Splice Site Interaction Affects U2AF[IMAGE] Binding to the Downstream 3` Splice Site. J. Biol. Chem. 270: 4031-4036 [Abstract] [Full Text]  
• Berget, S. M., Berget, S. M. (1995). Exon Recognition in Vertebrate Splicing. J. Biol. Chem. 270: 2411-2414 [Full Text]  
• Lutz, C S, Alwine, J C (1994). Direct interaction of the U1 snRNP-A protein with the upstream efficiency element of the SV40 late polyadenylation signal.. Genes Dev. 8: 576-586 [Abstract]  
• Lavigueur, A, La Branche, H, Kornblihtt, A R, Chabot, B (1993). A splicing enhancer in the human fibronectin alternate ED1 exon interacts with SR proteins and stimulates U2 snRNP binding.. Genes Dev. 7: 2405-2417 [Abstract]  
• Wassarman, K M, Steitz, J A (1993). Association with terminal exons in pre-mRNAs: a new role for the U1 snRNP?. Genes Dev. 7: 647-659 [Abstract]  
• Hoffman, B E, Grabowski, P J (1992). U1 snRNP targets an essential splicing factor, U2AF65, to the 3' splice site by a network of interactions spanning the exon.. Genes Dev. 6: 2554-2568 [Abstract]