Mutational analysis of the yeast U2 snRNA suggests a structural similarity to the catalytic core of group I introns.
We have used an in vitro reconstitution system to determine the effects of a large number of mutations in the highly conserved 5' terminal domain of the yeast U2 snRNA on pre-mRNA splicing. Whereas many mutations have little or no functional consequence, base substitutions in two regions were found to have drastic effects on pre-mRNA splicing. A previously unrecognized function for the U2 snRNA in the second step of splicing was found by alteration of the absolutely conserved sequence AGA upstream of the branch point recognition sequence. The effects of these mutations suggest the formation of a structure involving the U2 snRNA similar to the guanosine-binding site found in the catalytic core of group I introns.
McPheeters
D S
DS
Division of Biology, California Institute of Technology, Pasadena 91125.
Abelson
J
J
D000199:Actins / Q000235:genetics; D001483:Base Sequence; D016384:Consensus Sequence; D004252:DNA Mutational Analysis; D006860:Hydrogen Bonding; D066298:In Vitro Techniques; D007438:Introns; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D009694:Nucleic Acid Precursors / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012326:RNA Splicing; D012331:RNA, Fungal / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012342:RNA, Small Nuclear / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D016415:Sequence Alignment; D013329:Structure-Activity Relationship; D013997:Time Factors
D000199:Actins; D009694:Nucleic Acid Precursors; D012331:RNA, Fungal; D012333:RNA, Messenger; D012342:RNA, Small Nuclear