EXOSC9

This gene encodes a component of the human exosome, a exoribonuclease complex which processes and degrades RNA in the nucleus and cytoplasm. This component may play a role in mRNA degradation and the polymyositis/scleroderma autoantigen complex. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2011]

Full Name

Exosome Component 9

Research Area

Non-catalytic component of the RNA exosome complex which has 3'->5' exoribonuclease activity and participates in a multitude of cellular RNA processing and degradation events. In the nucleus, the RNA exosome complex is involved in proper maturation of stable RNA species such as rRNA, snRNA and snoRNA, in the elimination of RNA processing by-products and non-coding 'pervasive' transcripts, such as antisense RNA species and promoter-upstream transcripts (PROMPTs), and of mRNAs with processing defects, thereby limiting or excluding their export to the cytoplasm. The RNA exosome may be involved in Ig class switch recombination (CSR) and/or Ig variable region somatic hypermutation (SHM) by targeting AICDA deamination activity to transcribed dsDNA substrates. In the cytoplasm, the RNA exosome complex is involved in general mRNA turnover and specifically degrades inherently unstable mRNAs containing AU-rich elements (AREs) within their 3' untranslated regions, and in RNA surveillance pathways, preventing translation of aberrant mRNAs. It seems to be involved in degradation of histone mRNA. The catalytic inactive RNA exosome core complex of 9 subunits (Exo-9) is proposed to play a pivotal role in the binding and presentation of RNA for ribonucleolysis, and to serve as a scaffold for the association with catalytic subunits and accessory proteins or complexes. EXOSC9 binds to ARE-containing RNAs.

Biological Process

Exonucleolytic catabolism of deadenylated mRNA Source: UniProtKB
Exonucleolytic trimming to generate mature 3'-end of 5.8S rRNA from tricistronic rRNA transcript (SSU-rRNA, 5.8S rRNA, LSU-rRNA) Source: GO_Central
Immune response Source: UniProtKB
Nuclear mRNA surveillance Source: UniProtKB
Nuclear polyadenylation-dependent mRNA catabolic process Source: GO_Central
Nuclear polyadenylation-dependent rRNA catabolic process Source: UniProtKB
Nuclear polyadenylation-dependent tRNA catabolic process Source: GO_Central
Nuclear-transcribed mRNA catabolic process Source: UniProtKB
Nuclear-transcribed mRNA catabolic process, exonucleolytic, 3'-5' Source: GO_Central
Positive regulation of cell growth Source: UniProtKB
Positive regulation of transcription by RNA polymerase II Source: Ensembl
rRNA catabolic process Source: GO_Central
rRNA processing Source: UniProtKB
U1 snRNA 3'-end processing Source: GO_Central
U4 snRNA 3'-end processing Source: GO_Central
U5 snRNA 3'-end processing Source: GO_Central

Cellular Location

Nucleolus; Nucleus; Cytoplasm; Nucleoplasm. Colocalizes with SETX in nuclear foci upon induction of transcription-related DNA damage at the S phase (PubMed:24105744).
Isoform 1&2: Nucleolus
Isoform 3: Nucleus. Excluded from the nucleolus.

Involvement in disease

Pontocerebellar hypoplasia 1D (PCH1D):
An autosomal recessive neurologic disorder with onset at birth or in infancy, and characterized by progressive axonal motor neuronopathy, severe generalized hypotonia, respiratory insufficiency, and cerebellar atrophy. Death in childhood may occur.