Splicing function of mammalian U6 small nuclear RNA: conserved positions in central domain and helix I are essential during the first and second step of pre-mRNA splicing.
- 1 February 1994
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 91 (3), 903-907
- https://doi.org/10.1073/pnas.91.3.903
Abstract
On the basis of mutational analyses in yeast, the highly conserved ACAGAGA sequence of U6 small nuclear RNA (snRNA) and the adjacent U6-U2 helix I have been proposed to be part of the active center of the spliceosome. We report here a detailed analysis of the human U6 snRNA sequence requirements during the first and second step of splicing, using a mammalian in vitro splicing-complementation system and a mutational approach. Positions A53G54C55 (helix Ib) were identified as important specifically for the first step, but not for spliceosome assembly. A45 of the ACAGAGA sequence and U52 of helix Ia function during the second step; in addition, the bulge separating helices Ia and Ib appears critical for the second step. In contrast, no splicing-essential sequences could be identified in the central domain upstream of the ACAGAGA sequence. In sum, our data demonstrate for the mammalian splicing system that discrete positions within the ACAGAGA sequence and helix I of U6 snRNA function during the first and second step of splicing, suggesting that these two sequence elements are closely associated with the catalytic center of the spliceosome. Comparison with previous results in yeast indicates a fundamental conservation of the U6 snRNA function in the pre-mRNA splicing mechanism.Keywords
This publication has 23 references indexed in Scilit:
- Conformational changes of U6 RNA during the spliceosome cycle: an intramolecular helix is essential both for initiating the U4-U6 interaction and for the first step of slicing.Genes & Development, 1993
- Mutational analysis of the yeast U2 snRNA suggests a structural similarity to the catalytic core of group I intronsCell, 1992
- Association of U6 snRNA with the 5'-splice site region of pre-mRNA in the spliceosome.Genes & Development, 1992
- Biochemical Mechanisms of Constitutive and Regulated Pre-mRNA SplicingAnnual Review of Cell Biology, 1991
- Genetic evidence for base pairing between U2 and U6 snRNA in mammalian mRNA splicingNature, 1991
- Base pairing between U2 and U6 snRNAs is necessary for splicing of a mammalian pre-mRNANature, 1991
- mRNA-type introns in U6 small nuclear RNA genes: implications for the catalysis in pre-mRNA splicing.Genes & Development, 1991
- Multiple roles for U6 snRNA in the splicing pathway.Genes & Development, 1990
- Spliceosomal RNA U6 is remarkably conserved from yeast to mammalsNature, 1988
- Localization of a base-paired interaction between small nuclear RNAs U4 and U6 in intact U4/U6 ribonucleoprotein particles by psoralen cross-linkingJournal of Molecular Biology, 1985