title: Characterization of the human UBE3B gene: structure, expression, evolution, and alternative splicing.
abstract: E3 ubiquitin ligases target proteins for degradation by adding ubiquitin residues. We characterized full-length cDNAs for human and mouse UBE3B, a novel HECT-domain E3 ligase, and analyzed the structure of human UBE3B on chromosome 12q24.1. Alternative splicing of exon 20 of UBE3B generated two major transcripts. The 5.7-kb mRNA lacked exon 20 and encoded a full-length protein ligase, variant 1 (UBE3B_v1). A second transcript contained a 97-bp insertion encoded by exon 20 that introduced an in-frame stop codon. The predicted protein (UBE3B_v2) would lack the HECT domain and would be nonfunctional, since the HECT domain constitutes the active site for ubiquitin transfer. No alternative splicing was observed in this region of mouse UBE3B. Elimination of the HECT domain by alternative splicing has not been reported in any genes encoding HECT domain ligases and may represent a novel mechanism in regulating intracellular levels of functional HECT-domain ligases.
authors.affiliation: Kresge Hearing Research Institute, Department of Otolaryngology/Head-Neck Surgery, University of Michigan Medical School, Ann Arbor, MI 48109-0648, USA.
authors.forename: Tzy-Wen L
authors.initials: TW
authors.lastname: Gong
authors.forename: Li
authors.initials: L
authors.lastname: Huang
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Warner
authors.forename: Margaret I
authors.initials: MI
authors.lastname: Lomax
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D018076:DNA, Complementary / Q000235:genetics; D005786:Gene Expression Regulation; D020868:Gene Silencing; D020662:Guanine Nucleotide Exchange Factors; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D011506:Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D020662:Guanine Nucleotide Exchange Factors; C486527:Herc2 protein, mouse; D011506:Proteins; C482647:UBE3B protein, human; C118566:HERC2 protein, human; D044767:Ubiquitin-Protein Ligases