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Characterization of the human UBE3B gene: structure, expression, evolution, and alternative splicing
Tzy-Wen L Gong1, Li Huang, Steven J Warner
1Kresge Hearing Research Institute, Department of Otolaryngology/Head-Neck Surgery, University of Michigan Medical School, Ann Arbor, MI 48109-0648, USA.
Genomics
|July 3, 2003
Summary
Human UBE3B exhibits alternative splicing, creating a nonfunctional variant lacking the HECT domain. This novel mechanism may regulate functional HECT-domain ligase levels.
Area of Science:
- Biochemistry
- Molecular Biology
- Genetics
Background:
- E3 ubiquitin ligases are crucial enzymes that mediate protein degradation via ubiquitination.
- UBE3B is identified as a novel HECT-domain E3 ligase involved in this process.
Purpose of the Study:
- To characterize the full-length cDNAs of human and mouse UBE3B.
- To analyze the genomic structure of human UBE3B and investigate alternative splicing events.
Main Methods:
- Full-length cDNA characterization for human and mouse UBE3B.
- Analysis of human UBE3B gene structure at chromosome 12q24.1.
- Identification and comparison of alternative splicing transcripts.
Main Results:
- Two major human UBE3B transcripts were identified due to alternative splicing of exon 20.
- UBE3B variant 1 (UBE3B_v1) encodes a full-length functional ligase.
- UBE3B variant 2 (UBE3B_v2) results from exon 20 insertion, introducing a stop codon and leading to a nonfunctional protein lacking the HECT domain.
- No alternative splicing was observed in the corresponding region of mouse UBE3B.
Conclusions:
- Alternative splicing of UBE3B exon 20 generates functional and nonfunctional protein variants.
- The generation of a nonfunctional UBE3B variant by HECT domain elimination via alternative splicing is a novel finding among HECT-domain ligases.
- This mechanism may represent a new way to regulate intracellular levels of active HECT-domain ligases.