Small nucleolar RNA SNORD75

{{Infobox rfam

| Name = Small nucleolar RNA SNORD75

| image = RF00612.jpg

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| caption = Predicted secondary structure and sequence conservation of SNORD75

| Symbol = SNORD75

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| Rfam = RF00612

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| RNA_type = Gene; snRNA; snoRNA; C/D-box

| Tax_domain = Eukaryota

| GO = {{GO|0006396}} {{GO|0005730}}

| SO = {{SO|0000593}}

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In molecular biology, Small Nucleolar RNA SNORD75 (also known as U75) is a non-coding RNA (ncRNA) molecule which functions in the biogenesis (modification) of other small nuclear RNAs (snRNAs). This type of modifying RNA is located in the nucleolus of the eukaryotic cell which is a major site of snRNA biogenesis. It is known as a small nucleolar RNA (snoRNA) and also often referred to as a guide RNA.

U75 (SNORD75) belongs to the C/D box class of snoRNAs which contain the C (UGAUGA) and D (CUGA) box motifs. Most of the members of the box C/D family function in directing site-specific 2′-O-methylation of substrate RNAs.{{cite journal | vauthors = Galardi S, Fatica A, Bachi A, Scaloni A, Presutti C, Bozzoni I | title = Purified box C/D snoRNPs are able to reproduce site-specific 2′-O-methylation of target RNA in vitro | journal = Molecular and Cellular Biology | volume = 22 | issue = 19 | pages = 6663–6668 | date = October 2002 | pmid = 12215523 | pmc = 134041 | doi = 10.1128/MCB.22.19.6663-6668.2002 }}

The mouse snoRNA Z19 is orthologous to human U75. U75 is predicted to guide the 2′-O-ribose methylation of 28S ribosomal RNA (rRNA) residue C4032.{{cite journal | vauthors = Lestrade L, Weber MJ | title = snoRNA-LBME-db, a comprehensive database of human H/ACA and C/D box snoRNAs | journal = Nucleic Acids Research | volume = 34 | issue = Database issue | pages = D158–162 | date = January 2006 | pmid = 16381836 | pmc = 1347365 | doi = 10.1093/nar/gkj002 | citeseerx = 10.1.1.105.7552 }}

In humans U75 shares the same non-protein coding host gene (gas5) with 9 other snoRNAs (U44, U47, U74, U76, U77, U78, U79, U80 and U81).{{cite journal | vauthors = Smith CM, Steitz JA | title = Classification of gas5 as a multi-small-nucleolar-RNA (snoRNA) host gene and a member of the 5′-terminal oligopyrimidine gene family reveals common features of snoRNA host genes | journal = Molecular and Cellular Biology | volume = 18 | issue = 12 | pages = 6897–6909 | date = December 1998 | pmid = 9819378 | pmc = 109273 | doi = 10.1128/mcb.18.12.6897 | url = }}