title: Pre-mRNA splicing: the discovery of a new spliceosome doubles the challenge.
abstract: A rare class of pre-mRNA introns with non-canonical consensus sequences has been identified in metazoan genes. The novel, low-abundance spliceosome that excises these introns contains one small nuclear ribonucleoprotein (snRNP) in common with the major spliceosome (U5) and four snRNPs that are distinct from, but structurally and functionally analogous to U1, U2 and U4-U6. The architecture of RNA components at the presumptive core of the AT-AC splicesome supports current models of the spliceosomal active center and raises tantalizing questions about spliceosome evolution.
authors.affiliation: Division of Infectious Diseases, Academia Sinica, Nankang, Taipei, Taiwan, Republic of China.
authors.forename: W Y
authors.initials: WY
authors.lastname: Tarn
authors.forename: J A
authors.initials: JA
authors.lastname: Steitz
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D012322:RNA Precursors / Q000737:chemistry / Q000235:genetics*; D012326:RNA Splicing; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics*; D017414:Ribonucleoprotein, U4-U6 Small Nuclear / Q000235:genetics / Q000378:metabolism; D017411:Ribonucleoproteins, Small Nuclear / Q000235:genetics* / Q000378:metabolism; D017381:Spliceosomes / Q000235:genetics* / Q000378:metabolism*
chemical_list: D012322:RNA Precursors; D012333:RNA, Messenger; D017414:Ribonucleoprotein, U4-U6 Small Nuclear; D017411:Ribonucleoproteins, Small Nuclear; C098762:U11 small nuclear ribonucleoprotein, human; C552126:U11-U12 small nuclear ribonucleoprotein