title: Arabidopsis thaliana exosome subunit AtRrp4p is a hydrolytic 3'-->5' exonuclease containing S1 and KH RNA-binding domains.
abstract: The exosome, an evolutionarily conserved complex of multiple 3'-->5' exoribonucleases, is responsible for a variety of RNA processing and degradation events in eukaryotes. In this report Arabidopsis thaliana AtRrp4p is shown to be an active 3'-->5' exonuclease that requires a free 3'-hydroxyl and degrades RNA hydrolytically and distributively, releasing nucleoside 5'-monophosphate products. AtRrp4p behaves as an approximately 500 kDa species during sedimentation through a 10-30% glycerol gradient, co-migrating with AtRrp41p, another exosome subunit, and it interacts in vitro with AtRrp41p, suggesting that it is also present in the plant cell as a subunit of the exosome. We found that, in addition to a previously reported S1-type RNA-binding domain, members of the Rrp4p family of proteins contain a KH-type RNA-binding domain in the C-terminal half and show that either domain alone can bind RNA. However, only the full-length protein is capable of degrading RNA and interacting with AtRrp41p.
authors.affiliation: Department of Biological Sciences, State University of New York at Albany, 1400 Washington Avenue, Albany, NY 12222, USA.
authors.forename: Julia A
authors.initials: JA
authors.lastname: Chekanova
authors.forename: James A
authors.initials: JA
authors.lastname: Dutko
authors.forename: I Saira
authors.initials: IS
authors.lastname: Mian
authors.forename: Dmitry A
authors.initials: DA
authors.lastname: Belostotsky
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D019295:Computational Biology; D005089:Exocytosis; D005092:Exonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005095:Exoribonucleases / Q000378:metabolism; D063326:Exosome Multienzyme Ribonuclease Complex; D020869:Gene Expression Profiling; D006801:Humans; D006868:Hydrolysis; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D018749:RNA, Plant / Q000032:analysis / Q000235:genetics; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment
chemical_list: D029681:Arabidopsis Proteins; D021122:Protein Subunits; D018749:RNA, Plant; D016601:RNA-Binding Proteins; C415835:EXOSC4 protein, human; D005092:Exonucleases; D005095:Exoribonucleases; D063326:Exosome Multienzyme Ribonuclease Complex; C485933:RRP41 protein, Arabidopsis