The mouse genome contains two expressed intronless retroposed pseudogenes for the sentrin/sumo-1/PIC1 conjugating enzyme Ubc9

• Published in: Molecular immunology 1998-11, Vol.35 (16), p.1057-1067
• Main Authors: Tsytsykova, Alla V, Tsitsikov, Erdyni N, Wright, Dowain A, Futcher, Bruce, Geha, Raif S
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Base Sequence; DNA Primers - genetics; Exons; fas Receptor - metabolism; Gene Expression; Genes; Genetic Complementation Test; Genome; Humans; Introns; Ligases - genetics; Ligases - metabolism; Mice; Molecular Sequence Data; Pseudogenes; Restriction Mapping; Retroelements; RNA, Messenger - genetics; RNA, Messenger - metabolism; Saccharomyces cerevisiae - genetics; SUMO-1 Protein; Ubiquitin-Conjugating Enzymes; Ubiquitins - metabolism
• ISSN: 0161-5890; 1872-9142
• DOI: 10.1016/S0161-5890(98)00094-7

The ubiquitin conjugating (ubc) E2 enzyme ubc-9 conjugates the ubiquitin-like peptide sentrin/SUMO-1/PIC1 to target proteins which include the Fas antigen. We show that the mouse genome contains four copies of the ubc-9 gene. These include a structural ubc-9 gene consisting of seven exons which encode a protein identical to human ubc-9, and three intronless processed pseudogenes. The open reading frames (ORF) of two of the pseudogenes, ubc9-ψ1 and ubc9-ψ2, correspond to the cDNA of ubc-9 and encode for proteins which differ from ubc9 by three and one amino acid substitutions respectively. The third pseudogene, ubc9-ψ3, contains many mutations and stop codons. ubc9-ψ1 and ubc9-ψ2 are flanked by 5′- and 3′-untranslated (UT) regions homologous to those of the structural ubc-9 gene. Both genes contain a polyA tail and direct repeats at both ends suggesting that they arose by mRNA retroposition. Both ubc9-ψ1 and ubc9-ψ2 are transcribed into mRNA in murine cells. In contrast to ubc9, the protein products of ubc9-ψ1 and ubc9-ψ2 fail to bind Fas and to complement an yeast conditional ubc9 mutant. These results suggest that ubc9-ψ1 and ubc9-ψ2 encode for proteins that may interact with targets that differ from those recognized by ubc-9.