title: The roles of intersubunit interactions in exosome stability.
abstract: In eukaryotes, at least 10 proteins associate in a 3'-5' exonuclease complex, the exosome, which is involved in the processing of many RNA species. A recent model for the exosome placed six RNase PH-related components in a hexameric ring core structure, with three S1 domain proteins associated with the ring surface. So far, however, this model lacks experimental support. Using a combination of RNA interference, complex affinity purification, and yeast two-hybrid approaches, we show here that the RNase PH homologues are important for maintenance of complex integrity. In contrast, the S1 domain proteins are not required for complex stability, although they are required for exosome function. Our results are partially consistent with the proposed model of the exosome, but indicate a different arrangement of the RNase PH proteins.
authors.affiliation: Zentrum für Molekulare Biologie, Heidelberg Universität, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany. aestevez@ipb.csic.es
authors.forename: Antonio M
authors.initials: AM
authors.lastname: Estévez
authors.forename: Ben
authors.initials: B
authors.lastname: Lehner
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Sanderson
authors.forename: Thomas
authors.initials: T
authors.lastname: Ruppert
authors.forename: Christine
authors.initials: C
authors.lastname: Clayton
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005786:Gene Expression Regulation; D006801:Humans; D008954:Models, Biological; D008969:Molecular Sequence Data; D021122:Protein Subunits / Q000737:chemistry; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000502:physiology; D013997:Time Factors; D014346:Trypanosoma brucei brucei / Q000235:genetics / Q000502:physiology*
chemical_list: D021122:Protein Subunits; D015800:Protozoan Proteins