Alternative titles; symbols
HGNC Approved Gene Symbol: RPS27A
Cytogenetic location: 2p16.1 Genomic coordinates (GRCh38): 2:55,231,903-55,235,853 (from NCBI)
Ubiquitin is a highly conserved 76-amino acid protein that plays a key role in protein degradation. Ubiquitin is synthesized as precursor proteins that consist either of polyubiquitin chains that are cleaved into moieties of the UBB (191339) or UBC (191340) types, or single ubiquitin moieties fused 5-prime to unrelated carboxyl extension proteins (UBA type) such as UBA52 (191321) and UBA80 (RPS27A).
By screening a liver cDNA library with probes for IGF1 (147440), Lund et al. (1985) obtained a partial cDNA encoding all but the N-terminal 4 amino acids of RPS27A. The deduced 156-amino acid protein contains ubiquitin plus an 80-residue C-terminal extension. Northern blot analysis revealed expression of an 0.6-kb transcript in liver and mammary carcinoma cells.
Pancre et al. (1991) obtained a full-length cDNA encoding RPS27A by screening a Jurkat cDNA library for a platelet activity suppressive lymphokine.
Using differential screening of mammary carcinoma and fibroadenoma tumors, Adams et al. (1992) isolated a cDNA encoding RPS27A, which they called HUBCEP80. They detected higher levels of RPS27A in nonmalignant fibroadenoma.
Monia et al. (1989) developed a system for expression of human ubiquitin carboxyl extension proteins in prokaryotic and eukaryotic hosts. When expressed in Saccharomyces cerevisiae, the intact proteins were rapidly processed to free ubiquitin monomer and extension protein. Furthermore, expression in this host conferred a slow growth phenotype mediated by the extension protein. Expression in E. coli did not result in processing of the fusion proteins. However, when the expressed fusion proteins were purified from E. coli and incubated with a rabbit reticulocyte extract, the proteins were rapidly processed to free ubiquitin monomer and extension protein. These results showed that human ubiquitin carboxyl extension proteins are processed to ubiquitin and extension protein when expressed in eukaryotic but not prokaryotic cells and that pre- and cotranslational events are not necessary for their processing.
By PCR and YAC analysis, Kirschner and Stratakis (2000) determined that the RPS27A gene contains 6 exons, with the initiator ATG in exon 2, and spans approximately 2.9 kb. Promoter analysis identified a GC-rich region with an SP1 box but no TATA or CAAT boxes.
By radiation hybrid and physical mapping analyses, Kirschner and Stratakis (2000) mapped the RPS27A gene to 2p16. They identified a pseudogene on chromosome 17.
Adams, S. M., Sharp, M. G. F., Walker, R. A., Brammar, W. J., Varley, J. M. Differential expression of translation-associated genes in benign and malignant human breast tumours. Brit. J. Cancer 65: 65-71, 1992. [PubMed: 1370760] [Full Text: https://doi.org/10.1038/bjc.1992.12]
Kirschner, L. S., Stratakis, C. A. Structure of the human ubiquitin fusion gene Uba80 (RPS27a) and one of its pseudogenes. Biochem. Biophys. Res. Commun. 270: 1106-1110, 2000. [PubMed: 10772958] [Full Text: https://doi.org/10.1006/bbrc.2000.2568]
Lund, P. K., Moats-Staats, B. M., Simmons, J. G., Hoyt, E., D'Ercole, A. J., Martin, F., Van Wyk, J. J. Nucleotide sequence analysis of a cDNA encoding human ubiquitin reveals that ubiquitin is synthesized as a precursor. J. Biol. Chem. 260: 7609-7613, 1985. [PubMed: 2581967]
Monia, B. P., Ecker, D. J., Jonnalagadda, S., Marsh, J., Gotlib, L., Butt, T. R., Crooke, S. T. Gene synthesis, expression, and processing of human ubiquitin carboxyl extension proteins. J. Biol. Chem. 264: 4093-4103, 1989. [PubMed: 2537304]
Pancre, V., Pierce, R. J., Fournier, F., Mehtali, M., Delanoye, A., Capron, A., Auriault, C. Effect of ubiquitin on platelet functions: possible identity with platelet activity suppressive lymphokine (PASL). Europ. J. Immun. 21: 2735-2741, 1991. [PubMed: 1657614] [Full Text: https://doi.org/10.1002/eji.1830211113]