Group II introns deleted for multiple substructures retain self-splicing activity.
Open Access
- 1 May 1992
- journal article
- Published by Taylor & Francis in Molecular and Cellular Biology
- Vol. 12 (5), 1950-1958
- https://doi.org/10.1128/mcb.12.5.1950
Abstract
Group II introns can be folded into highly conserved secondary structures with six major substructures or domains. Domains 1 and 5 are known to play key roles in self-splicing, while the roles of domains 2, 3, 4, and 6 are less clear. A trans assay for domain 5 function has been developed which indicates that domain 5 has a binding site on the precursor RNA that is not predicted from any secondary structure element. In this study, the self-splicing group II intron 5 gamma of the coxI gene of yeast mitochondrial DNA was deleted for various intron domains, singly and in combinations. Those mutant introns were characterized for self-splicing reactions in vitro as a means of locating the domain 5 binding site. A single deletion of domain 2, 3, 4, or 6 does not block in vitro reactions at either splice junction, though the deletion of domain 6 reduces the fidelity of 3' splice site selection somewhat. Even the triple deletion lacking domains 2, 4, and 6 retains some self-splicing activity. The deletion of domains 2, 3, 4, and 6 blocks the reaction at the 3' splice junction but not at the 5' junction. From these results, we conclude that the binding site for domain 5 is within domain 1 and that the complex of 5' exon, domain 1, and domain 5 (plus short connecting sequences) constitutes the essential catalytic core of this intron.Keywords
This publication has 22 references indexed in Scilit:
- Structural requirements for selection of 5′- and 3′ splice sites of group II intronsNucleic Acids Research, 1991
- Splice site selection and role of the lariat in a group II intronJournal of Molecular Biology, 1991
- Self-splicing group II and nuclear pre-mRNA introns: how similar are they?Trends in Biochemical Sciences, 1990
- Minimum secondary structure requirements for catalytic activity of a self-splicing group I intronBiochemistry, 1990
- Base-pairing interactions involving the 5′ and 3′-terminal nucleotides of group II self-splicing intronsJournal of Molecular Biology, 1990
- Effect of deletions at structural domains of group II intron bI1 on self-splicing in vitroJournal of Molecular Biology, 1990
- A self-splicing group II intron in the mitochondrial large subunit rRNA (LSUrRNA) gene of the eukaryotic algaScenedesmus obliquusNucleic Acids Research, 1990
- Selection of cryptic 5′ splice sites by group II intron RNAsin vitroNucleic Acids Research, 1988
- Self-splicing of group II introns in vitro: Mapping of the branch point and mutational inhibition of lariat formationCell, 1986
- Excised group II introns in yeast mitochondria are lariats and can be formed by self-splicing in vitroCell, 1986