Alternative titles; symbols
HGNC Approved Gene Symbol: EXOSC7
Cytogenetic location: 3p21.31 Genomic coordinates (GRCh38) : 3:44,976,244-45,012,668 (from NCBI)
By sequencing cDNAs randomly selected from a cDNA library derived from the human immature myeloid cell line KG-1, Nagase et al. (1995) isolated a cDNA encoding RRP42, which they designated KIAA0116. The predicted 290-amino acid KIAA0116 protein is 26.7% identical to the 75-kD autoantigen (PMSCL1; 606180) over a 225-amino acid region. Northern blot analysis detected expression of KIAA0116 in all tissues tested.
Inherently unstable mammalian mRNAs contain AU-rich elements (AREs) within their 3-prime untranslated regions. In yeast, 3-prime-to-5-prime mRNA degradation is mediated by the exosome, a multisubunit particle. Chen et al. (2001) purified and characterized the human exosome by mass spectrometry and found its composition to be similar to its yeast counterpart. They identified the following protein subunits within the human exosome: p7, which is homologous to the yeast Rrp4 protein (602238); p8, which is homologous to the yeast Rrp42 protein; p9, which is homologous to the yeast Rrp43 protein (OIP2; 606019); p10, which is homologous to the yeast Rrp40 protein (606489); p11, which is homologous to the yeast Mtr3 protein (606490); p12A, which is homologous to the yeast Rrp41 protein (606491); p12B, which is homologous to the yeast Rrp46 protein (606492); and p13, which is homologous to the yeast Csl4 protein (606493). They also identified 2 exosome-associated factors, p1 (600478) and p14 (MPP6; 605500), that were not homologous to any yeast exosome components.
Using a cell-free RNA decay system, Chen et al. (2001) demonstrated that the mammalian exosome is required for rapid degradation of ARE-containing RNAs but not for poly(A) shortening. They found that the mammalian exosome does not recognize ARE-containing RNAs on its own. ARE recognition required certain ARE-binding proteins that could interact with the exosome and recruit it to unstable RNAs, thereby promoting their rapid degradation.
Using mammalian 2-hybrid and GST pull-down analyses, Raijmakers et al. (2002) found that the CSL4 protein, but not mutant forms lacking N- or C-terminal residues, interacted directly with RRP42 and RRP46. The deletion mutants were also unable to interact with the exosome. RRP42 and RRP46 did not interact with each other.
By analysis of a panel of human/rodent hybrid cell lines, Nagase et al. (1995) mapped the KIAA0116 gene to chromosome 3.
Gross (2014) mapped the EXOSC7 gene to chromosome 3p21.31 based on an alignment of the EXOSC7 sequence (GenBank BC012831) with the genomic sequence (GRCh37).
Chen, C.-Y., Gherzi, R., Ong, S.-E., Chan, E. L., Raijmakers, R., Pruijn, G. J. M., Stoecklin, G., Moroni, C., Mann, M., Karin, M. AU binding proteins recruit the exosome to degrade ARE-containing mRNAs. Cell 107: 451-464, 2001. [PubMed: 11719186] [Full Text: https://doi.org/10.1016/s0092-8674(01)00578-5]
Gross, M. B. Personal Communication. Baltimore, Md. 6/25/2014.
Nagase, T, Miyajima, N, Tanaka, A., Sazuka, T., Seki, N., Sato, S., Tabata, S., Ishikawa, K., Kawarabayashi, Y., Kotani, H., Nomura, N. Prediction of the coding sequences of unidentified human genes. III. The coding sequences of 40 new genes (KIAA0081-KIAA0120) deduced by analysis of cDNA clones from human cell line KG-1. DNA Res. 2: 37-43, 1995. [PubMed: 7788527] [Full Text: https://doi.org/10.1093/dnares/2.1.37]
Raijmakers, R., Noordman, Y. E., van Venrooij, W. J., Pruijn, G. J. M. Protein-protein interactions of hCsl4p with other human exosome subunits. J. Molec. Biol. 315: 809-818, 2002. [PubMed: 11812149] [Full Text: https://doi.org/10.1006/jmbi.2001.5265]