Structure of the Human Ubiquitin Fusion Gene Uba80 (RPS27a) and One of Its Pseudogenes

Abstract

Ubiquitin is a highly conserved 76 amino acid protein that is generated in the cell by proteolysis of larger proteins containing either polyubiquitin chains or ubiquitin fused to carboxyl extension proteins (CEPs). In humans, the two human ubiquitin-CEP genes are Uba80 and Uba52, which code for ubiquitin fused to ribosomal protein S27a and L40, respectively. Working from a recently generated physical map of human chromosome 2p16, we determined the genetic and physical location and the genomic structure of the Uba80 gene in its entirety. A comparison of Uba80 to Uba52 revealed that the two genes share a conserved 5-end structure, but that the structure of the ubiquitin coding regions was not conserved. Analysis of 400 bp of the promoter of Uba80 revealed strong similarity not only to the Uba52 promoter, but also to the other known human ribosomal gene promoters that have been identified to date. Homology searches also detected the presence of a pseudogene for Uba80, and the structure of this sequence feature is also reported.

Isolation and Functional Analysis of Mouse UbA52 Gene and Its Relevance to Diabetic Nephropathy

“…The mouse cDNA sequences in the open reading frame revealed 85% homology with human UbA52. Finally, the mouse UbA52 protein sequence was identical to that of the human and also of the UbA80 up to the 60 th amino acid residue (34).…”

Altered dynamics of ubiquitin hybrid proteins during tumor cell apoptosis

“…The effect of 4HPR on Uba80 and Uba52 promoter activity was tested further by transiently transfecting Hep3B cells with Uba80-Luc and Uba52-Luc, which contain the human Uba80 and Uba52 promoters, respectively, linked to a luciferase reporter gene (Figure 1f). 20, 21 The decrease in luciferase activity relative to the level in untreated control cells indicates that 4HPR decreased the level of Uba80 and Uba52 promoter activation in the transfected Hep3B cells. This suggests that the apoptogenic drugs increased Uba80 and Uba52 mRNA at the post-transcriptional level.…”

“…Hep3B or SK-HEP-1 cells were transfected with the pGL3B-Uba52 construct using lipofectin (Gibco–BRL, Grand Island, NY, USA) as described previously. 20 Luciferase activity was measured using the Dual-Luciferase Reporter Assay System (Promega, Madison, WI, USA), according to the manufacturer's instructions, and was normalized by the Renilla luciferase assay.…”

Dynamic transcription of ubiquitin genes under basal and stressful conditions and new insights into the multiple UBC transcript variants

“…The use of multiple TSS is widely spread in the human genome (Liang et al, 2014) and ubiquitin genes are not an exception: multiple start sites have indeed been described for the RPS27A gene (Kirschner and Stratakis, 2000) and also for the chicken testis polyubiquitin gene UbI (Mezquita et al, 1997). However, as far as we know, afterwards the study of Nenoi in 1996(Nenoi et al, 1996, that sets the hallmarks of the UBC gene structure, including the TSS, and our recent molecular studies Bianchi et al, 2009;Radici et al, 2013) no other investigations aimed to define the boundary between the true promoter and the transcribed region of UBC gene were performed.…”