HGNC Approved Gene Symbol: WDR13
Cytogenetic location: Xp11.23 Genomic coordinates (GRCh38) : X:48,597,492-48,608,869 (from NCBI)
WDR13 belongs to a large family of tryptophan and aspartate (WD) repeat proteins that provide platforms for protein-protein interactions. WD repeat proteins function in cell cycle regulation, transcription, chromatin organization, and protein trafficking (summary by Singh et al., 2012).
By screening a human testis cDNA library, Singh et al. (2003) cloned WDR13. The deduced 485-amino acid protein has a calculated molecular mass of 53 kD. The N-terminal domain of WDR13 contains several consensus phosphorylation sites, and the C terminus contains 6 WD repeats. Singh et al. (2003) also identified a splice variant that encodes a 393-amino acid protein with a calculated molecular mass of 43 kD. Northern blot analysis detected variable expression of transcripts at about 3.0 and 2.0 kb in all tissues examined. RNA dot blot analysis confirmed widespread expression in adult and fetal tissues. Transfection of the WDR13 splice variants in Chinese hamster ovary cells demonstrated expression of the 53-kD isoform in the nucleus and expression of the 43-kD isoform in both cytoplasm and nucleus.
By Northern blot analysis, Singh et al. (2012) detected an approximately 2-kb Wdr13 transcript in mouse testis and an approximately 4-kb Wdr13 transcript in mouse brain. Western blot analysis showed an approximately 45-kD protein in mouse testis, pancreas, islets, liver, and adipose tissue, with lower expression in muscle and acinar cells.
Singh et al. (2003) determined that the WDR13 gene contains 9 exons and spans 7.3 kb. The promoter region contains a GC box and binding sites for AP1 (see JUN, 165160), SP1 (189906), and GATA1 (305371).
By FISH and genomic sequence analysis, Singh et al. (2003) mapped the WDR13 gene to chromosome Xp11.23.
Singh et al. (2012) stated that the mouse Wdr13 gene maps to chromosome XA1.1.
Singh et al. (2012) found that overexpression of mouse Wdr13 in pancreatic MIN6 cells reduced cell proliferation, concomitant with elevated p21 (CDK1A; 116899) protein levels, with no change in expression of other cell cycle regulators. Knockdown of Wdr13 in MIN6 cells resulted in p21 downregulation. Chromatin immunoprecipitation analysis revealed occupancy of the p21 promoter by Wdr13.
Singh et al. (2012) found that male and female Wdr13 knockout (KO) mice were viable and fertile and had no overt phenotype except that they became heavier than wildtype littermates beginning around 9 months of age. Increased weight in Wdr13 KO mice was primarily due to increased body fat caused by adipocyte hypertrophy with no change in adipocyte number. Wdr13 KO mice also showed increased pancreatic mass with enhanced beta cell proliferation, causing insulin hypersecretion and elevated glucose clearance. Enhanced beta cell proliferation in Wdr13 KO pancreas was accompanied by increased expression of p21.
Singh, B. N., Suresh, A., UmaPrasad, G., Subramanian, S., Sultana, M., Goel, S., Kumar, S., Singh, L. A highly conserved human gene encoding a novel member of WD-repeat family of proteins (WDR13). Genomics 81: 315-328, 2003. [PubMed: 12659815] [Full Text: https://doi.org/10.1016/s0888-7543(02)00036-8]
Singh, V. P., Lakshmi, B. J., Singh, S., Shah, V., Goel, S., Sarathi, D. P., Kumar, S. Lack of Wdr13 gene in mice leads to enhanced pancreatic beta cell proliferation, hyperinsulinemia and mild obesity. PLoS One 7: e38685, 2012. Note: Electronic Article. [PubMed: 22715406] [Full Text: https://doi.org/10.1371/journal.pone.0038685]