title: RS domain-splicing signal interactions in splicing of U12-type and U2-type introns.
abstract: Serine-arginine (SR) proteins are general metazoan splicing factors that contain an essential arginine/serine-rich (RS) domain. On typical U2-type introns, RS domains contact the branchpoint and 5' splice site to promote base-pairing with U small nuclear RNAs (snRNAs). Here we analyze the role of SR proteins in splicing of U12-type introns and in the second step of U2-type intron splicing. We show that RS domains contact the branchpoint and 5' splice site of a U12-type intron. On a U2-type intron, we find that the RS domain contacts the site of the U6 snRNA-5' splice site interaction during the first step of splicing and shifts to contact the site of the U5 snRNA-exon 1 interaction during the second step. Our results reveal alternative interactions between the RS domain and 5' splice site region that coincide with remodeling of the spliceosome between the two catalytic steps.
authors.affiliation: Howard Hughes Medical Institute and Programs in Gene Function and Expression and Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
authors.forename: Haihong
authors.initials: H
authors.lastname: Shen
authors.forename: Michael R
authors.initials: MR
authors.lastname: Green
mesh_terms: D001483:Base Sequence; D005091:Exons; D006367:HeLa Cells; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D022821:RNA Splice Sites; D012326:RNA Splicing; D012342:RNA, Small Nuclear / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D000068103:Serine-Arginine Splicing Factors; D017381:Spliceosomes / Q000378:metabolism*
chemical_list: D009687:Nuclear Proteins; D022821:RNA Splice Sites; D012342:RNA, Small Nuclear; D016601:RNA-Binding Proteins; C405485:U5 small nuclear RNA; C405486:U6 small nuclear RNA; D000068103:Serine-Arginine Splicing Factors