Sequence requirements for branch formation in a group II self-splicing intron.
Evidence is presented for the existence of a specific intron-intron interaction, necessary for the formation of the branched product in the self-splicing reaction of a group II yeast mitochondrial intron. Trans-splicing reactions involving two RNA molecules (5' exon with covalently linked regions of intron and intron with covalently linked 3' exon) show that the presence of portions of intron domain I on the 5' molecule is necessary for the formation of branched products which are not seen with shorter 5' molecules. Modification/interference reactions show regions necesary for branch-formation and support a major role for specific regions of intron domain I. Further experiments, utilizing a truncated 3' molecule that is missing the conserved branchpoint nucleotide, indicate that domain VI may be required for a successful domain I interaction. A model for the formation of a proper branched structure includes implications for both cis and trans configurations.
Altura
R
R
Department of Biology, Brandeis University, Waltham, MA 02254.
Rymond
B
B
Seraphin
B
B
Rosbash
M
M
D001483:Base Sequence; D004272:DNA, Mitochondrial / Q000235:genetics*; D005800:Genes, Fungal; D007438:Introns; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012326:RNA Splicing; D012331:RNA, Fungal / Q000235:genetics*; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014158:Transcription, Genetic
D004272:DNA, Mitochondrial; D012331:RNA, Fungal