title: Splicing diversity revealed by reduced spliceosomes in C. merolae and other organisms.
abstract: Pre-mRNA splicing has been considered one of the hallmarks of eukaryotes, yet its diversity is astonishing: the number of substrate introns for splicing ranges from hundreds of thousands in humans to a mere handful in certain parasites. The catalytic machinery that carries out splicing, the spliceosome, is similarly diverse, with over 300 associated proteins in humans to a few tens in other organisms. In this Point of View, we discuss recent work characterizing the reduced spliceosome of the acidophilic red alga Cyanidioschyzon merolae, which further highlights the diversity of splicing in that it does not possess the U1 snRNP that is characteristically responsible for 5' splice site recognition. Comparisons to other organisms with reduced spliceosomes, such as microsporidia, trypanosomes, and Giardia, help to identify the most highly conserved splicing factors, pointing to the essential core of this complex machine. These observations argue for increased exploration of important biochemical processes through study of a wider ranger of organisms.
authors.affiliation: a Alberta RNA Research and Training Institute and Department of Biological Sciences ; University of Lethbridge ; Lethbridge , Alberta , Canada.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Hudson
authors.affiliation: b Department of Chemistry ; University of Northern British Columbia ; Prince George , British Columbia , Canada.
authors.forename: Martha R
authors.initials: MR
authors.lastname: Stark
authors.affiliation: c Biodiversity Research Center and Department of Botany ; University of British Columbia ; Vancouver , British Columbia , Canada.
authors.forename: Naomi M
authors.initials: NM
authors.lastname: Fast
authors.affiliation: a Alberta RNA Research and Training Institute and Department of Biological Sciences ; University of Lethbridge ; Lethbridge , Alberta , Canada.
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Russell
authors.affiliation: b Department of Chemistry ; University of Northern British Columbia ; Prince George , British Columbia , Canada.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Rader
mesh_terms: D000818:Animals; D002384:Catalysis; D019143:Evolution, Molecular; D016829:Giardia lamblia / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007438:Introns; D012322:RNA Precursors / Q000235:genetics; D012326:RNA Splicing / Q000235:genetics*; D012342:RNA, Small Nuclear / Q000737:chemistry / Q000235:genetics; D000461:Rhodophyta / Q000235:genetics* / Q000378:metabolism*; D017381:Spliceosomes / Q000378:metabolism*
chemical_list: D012322:RNA Precursors; D012342:RNA, Small Nuclear
keywords: alga; evolution; intron; microsporidian; protist; reduced spliceosome; small nuclear RNA; spliceosome; spliceosome catalytic core; spliceosome diversity