NCBI Summary:
This gene encodes ubiquitin, one of the most conserved proteins known. Ubiquitin is required for ATP-dependent, nonlysosomal intracellular protein degradation of abnormal proteins and normal proteins with a rapid turnover. Ubiquitin is covalently bound to proteins to be degraded, and presumably labels these proteins for degradation. Ubiquitin also binds to histone H2A in actively transcribed regions but does not cause histone H2A degradation, suggesting that ubiquitin is also involved in regulation of gene expression. This gene consists of three direct repeats of the ubiquitin coding sequence with no spacer sequence. Consequently, the protein is expressed as a polyubiquitin precursor with a final amino acid after the last repeat. Aberrant form of this protein has been noticed in patients with Alzheimer's and Down syndrome.
General function
DNA Replication, Cell proliferation
Comment
Cellular localization
Nuclear
Comment
Ovarian function
Comment
Expression regulated by
Comment
Ovarian localization
Oocyte
Comment
The Mouse Polyubiquitin Gene Ubb is Essential for Meiotic Progression. Ryu KY et al. Ubiquitin is encoded in mice by two polyubiquitin genes Ubb and Ubc that are considered to be stress-inducible, and two constitutively expressed monoubiquitin (Uba) genes. Here we report that targeted disruption of Ubb results in male and female infertility due to failure of germ cells to progress through meiosis I and hypogonadism. In the absence of Ubb, spermatocytes and oocytes arrest during meiotic prophase, before metaphase of the first meiotic division. Although cellular ubiquitin levels are believed to be maintained by a combination of functional redundancy among the four ubiquitin genes, stress-inducibility of the two polyubiquitin genes and ubiquitin recycling by proteasome-associated isopeptidases, our results indicate that ubiquitin is required for and consumed during meiotic progression. The striking similarity of the meiotic phenotype in Ubb(-/-) germ cells to the sporulation defect in fission yeast lacking a polyubiquitin gene suggests that a meiotic role of polyubiquitin gene has been conserved throughout eukaryotic evolution.
Follicle stages
Comment
Phenotypes
Mutations
1 mutations
Species: mouse
Mutation name: None
type: null mutation fertility: infertile - ovarian defect Comment: The Mouse Polyubiquitin Gene Ubb is Essential for Meiotic Progression. Ryu KY et al. Ubiquitin is encoded in mice by two polyubiquitin genes Ubb and Ubc that are considered to be stress-inducible, and two constitutively expressed monoubiquitin (Uba) genes. Here we report that targeted disruption of Ubb results in male and female infertility due to failure of germ cells to progress through meiosis I and hypogonadism. In the absence of Ubb, spermatocytes and oocytes arrest during meiotic prophase, before metaphase of the first meiotic division. Although cellular ubiquitin levels are believed to be maintained by a combination of functional redundancy among the four ubiquitin genes, stress-inducibility of the two polyubiquitin genes and ubiquitin recycling by proteasome-associated isopeptidases, our results indicate that ubiquitin is required for and consumed during meiotic progression. The striking similarity of the meiotic phenotype in Ubb(-/-) germ cells to the sporulation defect in fission yeast lacking a polyubiquitin gene suggests that a meiotic role of polyubiquitin gene has been conserved throughout eukaryotic evolution.