title: Processing of snoRNAs as a new source of regulatory non-coding RNAs: snoRNA fragments form a new class of functional RNAs.
abstract: Recent experimental evidence suggests that most of the genome is transcribed into non-coding RNAs. The initial transcripts undergo further processing generating shorter, metabolically stable RNAs with diverse functions. Small nucleolar RNAs (snoRNAs) are non-coding RNAs that modify rRNAs, tRNAs, and snRNAs that were considered stable. We review evidence that snoRNAs undergo further processing. High-throughput sequencing and RNase protection experiments showed widespread expression of snoRNA fragments, known as snoRNA-derived RNAs (sdRNAs). Some sdRNAs resemble miRNAs, these can associate with argonaute proteins and influence translation. Other sdRNAs are longer, form complexes with hnRNPs and influence gene expression. C/D box snoRNA fragmentation patterns are conserved across multiple cell types, suggesting a processing event, rather than degradation. The loss of expression from genetic loci that generate canonical snoRNAs and processed snoRNAs results in diseases, such as Prader-Willi Syndrome, indicating possible physiological roles for processed snoRNAs. We propose that processed snoRNAs acquire new roles in gene expression and represent a new class of regulatory RNAs distinct from canonical snoRNAs.
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, College of Medicine, Lexington, KY, USA.
authors.forename: Marina
authors.initials: M
authors.lastname: Falaleeva
authors.forename: Stefan
authors.initials: S
authors.lastname: Stamm
mesh_terms: D060565:Argonaute Proteins; D005786:Gene Expression Regulation; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000378:metabolism; D006801:Humans; D011218:Prader-Willi Syndrome / Q000235:genetics; D014176:Protein Biosynthesis / Q000235:genetics; D012335:RNA, Ribosomal / Q000235:genetics; D020537:RNA, Small Nucleolar / Q000235:genetics* / Q000378:metabolism*; D012343:RNA, Transfer / Q000235:genetics
chemical_list: D060565:Argonaute Proteins; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D012335:RNA, Ribosomal; D020537:RNA, Small Nucleolar; D012343:RNA, Transfer