The enzymes of the ubiquitylation pathway play a pivotal role in a number of cellular processes including regulated and targeted proteosomal degradation of substrate proteins. Three classes of enzymes are involved in the process of ubiquitylation; activating enzymes (E1s), conjugating enzymes (E2s) and protein ligases (E3s). UBE2G1 is a member of the E2 conjugating enzyme family and cloning of the human gene was first described by Watanabe et al. (1996). UBE2G1 shares 74% sequence identity with UBC7 from C. elegans and a high degree of homology with UBC7 from other species. Expression of UBE2G1 and a helix-loop-helix transcription factor and member of the MYC/MAX superfamily (ROX/MNT) is decreased in medullabalastoma tumours. Haploinsufficiency of the human 17p13.3 region is associated with 35% to 50% of medulloblastomas, indicating the presence of one or more tumour suppressor genes which have not yet been identified (Cvekl et al., 2004).
Cvekl A, Jr., Zavadil J, Birshtein BK, Grotzer MA, Cvekl A (2004) Analysis of transcripts from 17p13.3 in medulloblastoma suggests ROX/MNT as a potential tumour suppressor gene. Eur J Cancer 40, 2525-32.
Watanabe TK, Kawai A, Fujiwara T, Maekawa H, Hirai Y, Nakamura Y, Takahashi E (1996) Molecular cloning of UBE2G, encoding a human skeletal muscle-specific ubiquitin-conjugating enzyme homologous to UBC7 of C. elegans. Cytogenet Cell Genet 74, 146-8.