EXOSC1
Description
The EXOSC1 (exosome component 1) is a protein-coding gene located on chromosome 10.
3'-5' exoribonuclease CSL4 homolog is an enzyme that in humans is encoded by the EXOSC1 gene. This gene encodes a core component of the exosome complex. The mammalian exosome is required for rapid degradation of AU rich element-containing RNAs but not for poly(A) shortening. The association of this protein with the exosome is mediated by protein-protein interactions with ribosomal RNA-processing protein 42 and ribosomal RNA-processing protein 46.
== Interactions == Exosome component 1 has been shown to interact with:
Exosome component 5, Exosome component 6, and Exosome component 7.
EXOSC1 is a non-catalytic component of the RNA exosome complex, which possesses 3'-to-5' exoribonuclease activity and participates in a variety of cellular RNA processing and degradation events. Within the nucleus, the RNA exosome complex contributes to the proper maturation of stable RNA species such as rRNA, snRNA, and snoRNA. It also eliminates RNA processing by-products and non-coding 'pervasive' transcripts, including antisense RNA species and promoter-upstream transcripts (PROMPTs). Additionally, it handles mRNAs with processing defects, limiting or preventing their export to the cytoplasm. The RNA exosome might be involved in Ig class switch recombination (CSR) and/or Ig variable region somatic hypermutation (SHM) by directing AICDA deamination activity towards transcribed dsDNA substrates. In the cytoplasm, the RNA exosome complex is involved in general mRNA turnover, specifically degrading inherently unstable mRNAs containing AU-rich elements (AREs) within their 3' untranslated regions. It also plays a role in RNA surveillance pathways, preventing the translation of aberrant mRNAs. Evidence suggests its involvement in the degradation of histone mRNA. The catalytically inactive RNA exosome core complex, composed of 9 subunits (Exo-9), is believed to play a crucial role in binding and presenting RNA for ribonucleolysis. It acts as a scaffold for the association with catalytic subunits and accessory proteins or complexes. As a peripheral component of the Exo-9 complex, EXOSC1 stabilizes the hexameric ring of RNase PH-domain subunits through interactions with EXOSC6 and EXOSC8.
EXOSC1 is also known as CGI-108, CSL4, Csl4p, PCH1F, SKI4, Ski4p, p13.
