HGNC Approved Gene Symbol: YPEL2Cytogenetic location: 17q22 Genomic coordinates (GRCh38): 17:59,331,654-59,401,731 (from NCBI)▼ Cloning and ExpressionBy sear...
HGNC Approved Gene Symbol: YPEL2
Cytogenetic location: 17q22 Genomic coordinates (GRCh38): 17:59,331,654-59,401,731 (from NCBI)
▼ Cloning and Expression
By searching for sequences similar to YPEL1 (608082), followed by 5-prime and 3-prime RACE of a testis cDNA library, Hosono et al. (2004) cloned YPEL2. The deduced 119-amino acid protein shares 100% amino acid identity with mouse and monkey Ypel2 and 45% identity with Drosophila Yippee. YPEL2 shares 85.0 to 96.6% amino acid identity with YPEL1, YPEL3 (609724), and YPEL4 (609725). All YPEL proteins contain an 86-amino acid YPEL consensus sequence. PCR analysis detected YPEL2 expression in adult heart, kidney, lung, pancreas, placenta, skeletal muscle, leukocytes, prostate, spleen, and testis, and in fetal brain, heart, kidney, liver, lung, skeletal muscle, and spleen. Immunofluorescent staining of COS-7 green monkey kidney cells localized monkey Ypel2 to the centrosome and nucleolus during interphase and at several punctate structures around the mitotic apparatus during the mitotic phase.
De Bruijn et al. (2020) assessed expression of YPEL2 in multiple healthy human tissues by qPCR, and observed ubiquitous expression in the tissues studied, with the highest relative expression in brain. YPEL2 expression was present in retinal tissue, and single-cell retinal RNAseq datasets revealed that YPEL2 is expressed at the highest levels in rod photoreceptor cells.
▼ Gene Structure
Hosono et al. (2004) determined that the YPEL2 gene contains 5 exons and spans about 70 kb. Exon 1 is untranslated. The mouse Ypel2 gene has the same structure.
By genomic sequence analysis, Hosono et al. (2004) mapped the human YPEL2 gene to chromosome 17q23.2 and the mouse Ypel2 gene to chromosome 11C.
In affected individuals from 22 families with autosomal dominant retinitis pigmentosa (RP17; 600852), de Bruijn et al. (2020) identified heterozygosity for 8 different structural variants (SVs) at chromosome 17q22. The SVs segregated with disease and were fully penetrant, and none were found in gnomAD or the Database of Genomic Variants. All of the RP17 SVs shared an 11.5-kb common duplicated or triplicated region (chr17:57,499,214-57,510,765; GRCh37), with unique breakpoints disrupting the genomic region extending from YPEL2 to the long noncoding RNA LINC01476. Analysis of breakpoint junction sequences demonstrated the presence of repetitive elements as well as microhomology, longer stretches of homology, or small insertions and/or deletions, suggesting that potential mechanisms for the SVs include a combination of (micro)homology-mediated repair and nonhomologous end-joining developed from reprogrammed patient fibroblasts showed that YPEL2 sits within its own topologically-associating domain (TAD), rich in enhancers with binding sites for retinal transcription factors. Hi-C maps of RP17 ROs revealed creation of neo-TADs with ectopic contacts between GDPD1 (616317) and the YPEL2 retinal enhancers, and modeling of all RP17 SVs was consistent with neo-TADs resulting in ectopic retinal-specific enhancer-GDPD1 accessibility. By qPCR in ROs, the authors confirmed increased expression of GDPD1 and of the retinal enhancer that enters the neo-TAD. The authors concluded that altered TAD structures resulting in increased retinal expression of GDPD1 is the likely convergent mechanism of disease, consistent with a dominant gain of function.