title: Phosphorothioate substitution identifies phosphate groups important for pre-mRNA splicing.
abstract: Substitution of pre-mRNA in vitro splicing substrates with alpha-phosphorothioate ribonucleotide analogs has multiple effects on the processes of spliceosome formation and splicing. A major effect of substitution is on the splicing cleavage/ligation reactions. Substitution at the 5' splice junction blocks the first cleavage/ligation reaction while substitution at the 3' splice junction blocks the second cleavage/ligation reaction. A second effect of phosphorothioate substitution is the inhibition of spliceosome formation. A substitution/interference assay was used to determine positions where substitution inhibits spliceosome formation or splicing. Substitution in the 3' splice site polypyrimidine tract was found to inhibit spliceosome formation and splicing. This effect was enhanced with multiple substitutions in the region. No sites of substitution within the exons were found which affected spliceosome formation or splicing.
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235.
authors.forename: K L
authors.initials: KL
authors.lastname: Maschhoff
authors.forename: R A
authors.initials: RA
authors.lastname: Padgett
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D005914:Globins / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010710:Phosphates / Q000378:metabolism*; D012322:RNA Precursors / Q000378:metabolism*; D012326:RNA Splicing / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D011817:Rabbits; D013873:Thionucleotides / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics
chemical_list: D010710:Phosphates; D012322:RNA Precursors; D012333:RNA, Messenger; D013873:Thionucleotides; D014764:Viral Proteins; D005914:Globins