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 Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Datta, B Articles by Weiner, A M Search for Related Content PubMed PubMed Citation Articles by Datta, B Articles by Weiner, A M

 Previous Article  |  Next Article 

Mol Cell Biol. 1993 September; 13(9): 5377-5382

The phylogenetically invariant ACAGAGA and AGC sequences of U6 small nuclear RNA are more tolerant of mutation in human cells than in Saccharomyces cerevisiae.

Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06510.

ABSTRACT

U6 small nuclear RNA (snRNA) is the most highly conserved of the five spliceosomal snRNAs that participate in nuclear mRNA splicing. The proposal that U6 snRNA plays a key catalytic role in splicing [D. Brow and C. Guthrie, Nature (London) 337:14-15, 1989] is supported by the phylogenetic conservation of U6, the sensitivity of U6 to mutation, cross-linking of U6 to the vicinity of the 5' splice site, and genetic evidence for extensive base pairing between U2 and U6 snRNAs. We chose to mutate the phylogenetically invariant 41-ACAGAGA-47 and 53-AGC-55 sequences of human U6 because certain point mutations within the homologous regions of Saccharomyces cerevisiae U6 selectively block the first or second step of mRNA splicing. We found that both sequences are more tolerant to mutation in human cells (assayed by transient expression in vivo) than in S. cerevisiae (assayed by effects on growth or in vitro splicing). These differences may reflect different rate-limiting steps in the particular assays used or differential reliance on redundant RNA-RNA or RNA-protein interactions. The ability of mutations in U6 nucleotides A-45 and A-53 to selectively block step 2 of splicing in S. cerevisiae had previously been construed as evidence that these residues might participate directly in the second chemical step of splicing; an indirect, structural role seems more likely because the equivalent mutations have no obvious phenotype in the human transient expression assay.

This article has been cited by other articles:

• Valadkhan, S., Mohammadi, A., Wachtel, C., Manley, J. L. (2007). Protein-free spliceosomal snRNAs catalyze a reaction that resembles the first step of splicing. RNA 13: 2300-2311 [Abstract] [Full Text]  
• LORKOVIC, Z. J., LEHNER, R., FORSTNER, C., BARTA, A. (2005). Evolutionary conservation of minor U12-type spliceosome between plants and humans. RNA 11: 1095-1107 [Abstract] [Full Text]  
• HILLIKER, A. K., STALEY, J. P. (2004). Multiple functions for the invariant AGC triad of U6 snRNA. RNA 10: 921-928 [Abstract] [Full Text]  
• Horowitz, D S, Krainer, A R (1997). A human protein required for the second step of pre-mRNA splicing is functionally related to a yeast splicing factor.. Genes Dev. 11: 139-151 [Abstract]  
• Field, D J, Friesen, J D (1996). Functionally redundant interactions between U2 and U6 spliceosomal snRNAs.. Genes Dev. 10: 489-501 [Abstract]  
• Hwang, D Y, Cohen, J B (1996). U1 snRNA promotes the selection of nearby 5' splice sites by U6 snRNA in mammalian cells.. Genes Dev. 10: 338-350 [Abstract]  
• Sun, J S, Manley, J L (1995). A novel U2-U6 snRNA structure is necessary for mammalian mRNA splicing.. Genes Dev. 9: 843-854 [Abstract]  
• Sontheimer, E., Steitz, J. (1993). The U5 and U6 small nuclear RNAs as active site components of the spliceosome. Science 262: 1989-1996 [Abstract]