Alternative titles; symbols
HGNC Approved Gene Symbol: CCDC80
Cytogenetic location: 3q13.2 Genomic coordinates (GRCh38) : 3:112,596,797-112,641,143 (from NCBI)
Mice deficient in the gene encoding bombesin-like receptor-3 (BRS3; 300107) exhibit mild late-onset obesity, hyperphagia, and reduced metabolic rates. By differential display using Brs3-deficient mice, followed by 5-prime RACE, Aoki et al. (2002) obtained a full-length cDNA encoding Urb (upregulated in Brs3-deficient mice). The predicted 949-amino acid Urb protein contains a highly hydrophobic N-terminal signal sequence, indicating that it is a secretory protein, 3 N-glycosylation sites, several pairs of basic amino acids, and a lysine-rich region containing nuclear localization signals. Three consensus repeat domains in Urb share about 30% amino acid identity with the fifth domain of the human SRPX protein (300187), suggesting that Urb may be functionally related to the sushi protein superfamily. The nucleotide sequences of Urb and rat Ssg1 share more than 90% identity, but several mismatches result in a frameshift, and the Ssg1 protein contains only 385 residues. RT-PCR analysis detected Urb mRNA in all mouse tissues examined, and Northern blot analysis revealed a 3.2-kb Urb mRNA in mouse white adipose tissue. In situ hybridization of mouse brain showed expression of Urb in the anterior olfactory nucleus, dorsal endopiriform nucleus, and choroid plexus; weak expression was observed in the cortex, main olfactory bulb, and piriform cortex.
Using real-time quantitative RT-PCR, Aoki et al. (2002) determined that expression of Urb was 4-fold higher in brown adipose tissue of 8-month-old Brs3-deficient mice than in wildtype mice. In contrast, no difference in Urb expression was observed in white adipose tissue of 8-month-old Brs3-deficient mice and wildtype mice. Expression of Urb was not increased in brown or white adipose tissue of Brs3-deficient mice at age 7 weeks, when Brs3-deficient mice and wildtype mice have similar body weights. Aoki et al. (2002) concluded that upregulated Urb expression is tissue-specific and may play a role in energy metabolism and the regulation of body weight.
By radiation hybrid analysis, Aoki et al. (2002) mapped the mouse Urb gene to chromosome 16 in a region that shows homology of synteny to human chromosome 3.
Aoki, K., Sun, Y.-J., Aoki, S., Wada, K., Wada, E. Cloning, expression, and mapping of a gene that is upregulated in adipose tissue of mice deficient in bombesin receptor subtype-3. Biochem. Biophys. Res. Commun. 290: 1282-1288, 2002. [PubMed: 11812002] [Full Text: https://doi.org/10.1006/bbrc.2002.6337]