Alternative titles; symbols
HGNC Approved Gene Symbol: SNORD115-1
Cytogenetic location: 15q11.2 Genomic coordinates (GRCh38) : 15:25,170,723-25,170,804 (from NCBI)
Small nucleolar RNAs (snoRNAs), such as SNORD115, are noncoding RNAs that are 60 to 300 nucleotides long. They typically function in guiding 2-prime-O-methylation and pseudouridylation in ribosomal RNAs (rRNAs), small nuclear RNAs (snRNAs), and tRNAs. SNORD115 appears to play a role in regulating alternative splicing. Multiple copies of the SNORD115 gene, including SNORD115-1, are located within the introns of a large primary noncoding transcript, SNHG14 (616259), that originates from the Prader-Willi syndrome (PWS; 176270) critical region on human chromosome 15q11-q13 (Kishore and Stamm, 2006; Runte et al., 2001).
By searching for small non-mRNAs specifically expressed in mouse brain, followed by searching human sequence databases, Cavaille et al. (2000) identified SNORD115, which they called HBII-52. HBII-52 is a C/D box snoRNA with a 5-prime C box, followed by a D-prime box, a C-prime box, an antisense box, and a 3-prime D box. Northern blot analysis detected expression of HBII-52 in human brain, but not in liver, muscle, lung, kidney, and heart. Cavaille et al. (2000) determined that HBII-52 maps to an imprinted region of chromosome 15 associated with Angelman syndrome (AS; 105830) and PWS. They concluded that HBII-52 is a paternally imprinted gene, since it was expressed in cortex RNA from a normal control brain and from an AS patient with a maternally inherited deletion, but was absent from cortex RNA from a PWS patient with a paternally inherited deletion and from a mouse model of PWS.
By genomic sequence analysis, Cavaille et al. (2000) identified 47 tandem copies of the SNORD115 gene on chromosome 15q11-q13. The SNORD115 copies are slightly divergent units of about 1.9 kb regularly spaced within a stretch of 99 kb.
Runte et al. (2001) determined that HBII-52 and several other snoRNAs are encoded within intronic segments of the long primary noncoding SNURF-SNRPN (182279) sense/UBE3A (601623) antisense transcript (SNHG14; 616259). All but 2 of the HBII-52 copies are located within introns between exons 63 and 144; the remaining 2 are located within exons.
Cavaille et al. (2000) identified an 18-nucleotide phylogenetically conserved region in HBII-52 complementary to a critical segment of the serotonin-2C receptor mRNA (HTR2C; 312861), suggesting that HBII-52 may have a role in processing HTR2C mRNA.
The snoRNA HBII-52 is contained within the Prader-Willi deleted region on chromosome 15q11 and exhibits sequence complementarity to the alternatively spliced exon Vb of the serotonin receptor HTR2C. Kishore and Stamm (2006) found that HBII-52 regulates alternative splicing of HTR2C by binding to a silencing element in exon Vb. Prader-Willi syndrome patients do not express HBII-52. They have different HTR2C mRNA isoforms than healthy individuals. Kishore and Stamm (2006) concluded that a snoRNA regulates the processing of an mRNA expressed from a gene located on a different chromosome, and the results indicate that a defect in pre-mRNA processing contributes to the Prader-Willi syndrome.
Using bioinformatic predictions and experimental verification, Kishore et al. (2010) identified 5 pre-mRNAs (DPM2, 603564; TAF1, 313650; RALGPS1, 614444; PBRM1, 606083; and CRHR1, 122561) containing alternative exons that are regulated by MBII-52, the mouse homolog of HBII-52. Analysis of a single member of the MBII-52 cluster of snoRNAs by RNase protection and Northern blot analysis showed that the MBII-52 expressing unit generated shorter RNAs that originate from the full-length MBII-52 snoRNA through additional processing steps. These novel RNAs associated with hnRNPs and not with proteins associated with canonical C/D box snoRNAs. Kishore et al. (2010) concluded that not a traditional C/D box snoRNA MBII-52, but a processed version lacking the snoRNA stem, is the predominant MBII-52 RNA missing in Prader-Willi syndrome. This processed snoRNA functions in alternative splice site selection.
Powell et al. (2013) stated that the SNORD115 and SNORD116 (see 605436) snoRNAs are processed from 2 distinct long noncoding RNA (lncRNA) host genes, 115HG and 116HG, respectively, that are transcribed as part of the same primary transcript originating from the imprinting control region (see 616259). By RNA FISH of adult mouse brain, Powell et al. (2013) found that 116Hg and 115Hg appeared as overlapping but distinct cloud-like domains in neuronal cell nuclei. These clouds were observed in neurons in several brain regions, but not in nonneuronal cells and not in liver or spleen. Both 116Hg and 115Hg lncRNA clouds increased in diameter during the first week of postnatal life and localized to the paternal decondensed allele of Snrpn Snrpn-Ube3a. The 116Hg and 115Hg clouds also increased in size during sleep.
Runte et al. (2005) found that individuals with complete deletion of all copies of HBII-52 had no obvious clinical phenotype, suggesting that HBII-52 does not play a major role in PWS.
Sato et al. (2007) reported a Japanese family in which a boy with AS and his asymptomatic mother and maternal grandfather all had a 1,487-kb deletion on chromosome 15, encompassing HBII-52. The mother was evaluated with regard to diagnostic criteria for PWS but the diagnosis was considered unlikely, suggesting that HBII-52 may not be important in the pathogenesis of PWS.
In a mouse model for PWS lacking expression of Mbii-52, Doe et al. (2009) showed an increase in editing, but not alternative splicing, of the Htr2c pre-RNA. This change in posttranscriptional modification was associated with alterations in a number of brain serotonin-related behaviors, including impulsive responding, locomotor activity and reactivity to palatable foodstuffs. For marble burying, a behavior not related to brain serotonin, loss of Mbii-52 was without effect. The specificity of the behavioral effects to changes in Htr2c function was further confirmed using drug challenges. These data illustrated the physiologic consequences of altered RNA editing of Htr2c linked to Mbii-52 loss that may underlie specific aspects of the complex PWS phenotype and point to an important functional role for this imprinted snoRNA.
Cavaille, J., Buiting, K., Kiefmann, M., Lalande, M., Brannan, C. I., Horsthemke, B., Bachellerie, J.-P., Brosius, J., Huttenhofer, A. Identification of brain-specific and imprinted small nucleolar RNA genes exhibiting an unusual genomic organization. Proc. Nat. Acad. Sci. 97: 14311-14316, 2000. [PubMed: 11106375] [Full Text: https://doi.org/10.1073/pnas.250426397]
Doe, C. M., Relkovic, D., Garfield, A. S., Dalley, J. W., Theobald, D. E. H., Humby, T., Wilkinson, L. S., Isles, A. R. Loss of imprinted snoRNA mbii-52 leads to increased 5htr2c pre-RNA editing and altered 5HT(2C)R-mediated behaviour. Hum. Molec. Genet. 18: 2140-2148, 2009. [PubMed: 19304781] [Full Text: https://doi.org/10.1093/hmg/ddp137]
Kishore, S., Khanna, A., Zhang, Z., Hui, J., Balwierz, P. J., Stefan, M., Beach, C., Nicholls, R. D., Zavolan, M., Stamm, S. The snoRNA MBII-52 (SNORD 115) is processed into smaller RNAs and regulates alternative splicing. Hum. Molec. Genet. 19: 1153-1164, 2010. [PubMed: 20053671] [Full Text: https://doi.org/10.1093/hmg/ddp585]
Kishore, S., Stamm, S. The snoRNA HBII-52 regulates alternative splicing of the serotonin receptor 2C. Science 311: 230-232, 2006. [PubMed: 16357227] [Full Text: https://doi.org/10.1126/science.1118265]
Powell, W. T., Coulson, R. L., Crary, F. K., Wong, S. S., Ach, R. A., Tsang, P., Yamada, N. A., Yasui, D. H., LaSalle, J. M. A Prader-Willi locus lncRNA cloud modulates diurnal genes and energy expenditure. Hum. Molec. Genet. 22: 4318-4328, 2013. [PubMed: 23771028] [Full Text: https://doi.org/10.1093/hmg/ddt281]
Runte, M., Huttenhofer, A., Gross, S., Kiefmann, M., Horsthemke, B., Buiting, K. The IC-SNURF-SNRPN transcript serves as a host for multiple small nucleolar RNA species and as an antisense RNA for UBE3A. Hum. Molec. Genet. 10: 2687-2700, 2001. [PubMed: 11726556] [Full Text: https://doi.org/10.1093/hmg/10.23.2687]
Runte, M., Varon, R., Horn, D., Horsthemke, B., Buiting, K. Exclusion of the C/D box snoRNA gene cluster HBII-52 from a major role in Prader-Willi syndrome. Hum. Genet. 116: 228-230, 2005. [PubMed: 15565282] [Full Text: https://doi.org/10.1007/s00439-004-1219-2]
Sato, K., Iwakoshi, M., Shimokawa, O., Sakai, H., Ohta, T., Saitoh, S., Miyake, N., Niikawa, N., Harada, N., Saitsu, H., Mizuguchi, T., Matsumoto, N. Angelman syndrome caused by an identical familial 1,487-kb deletion. (Letter) Am. J. Med. Genet. 143A: 98-101, 2007. [PubMed: 17152063] [Full Text: https://doi.org/10.1002/ajmg.a.31550]