Small Nucleolar RNA SNORD75 (also known as U75) is a non-coding RNA

Non-coding RNA

A non-coding RNA is a functional RNA molecule that is not translated into a protein. Less-frequently used synonyms are non-protein-coding RNA , non-messenger RNA and functional RNA . The term small RNA is often used for short bacterial ncRNAs...

 (ncRNA) molecule which functions in the biogenesis (modification) of other small nuclear RNAs

Small nuclear RNA

Small nuclear ribonucleic acid is a class of small RNA molecules that are found within the nucleus of eukaryotic cells. They are transcribed by RNA polymerase II or RNA polymerase III and are involved in a variety of important processes such as RNA splicing , regulation of transcription factors ...

 (snRNAs). This type of modifiying RNA is located in the nucleolus

Nucleolus

The nucleolus is a non-membrane bound structure composed of proteins and nucleic acids found within the nucleus. Ribosomal RNA is transcribed and assembled within the nucleolus...

 of the eukaryotic cell which is a major site of snRNA biogenesis. It is known as a small nucleolar RNA

SnoRNA

Small nucleolar RNAs are a class of small RNA molecules that primarily guide chemical modifications of other RNAs, mainly ribosomal RNAs, transfer RNAs and small nuclear RNAs...

 (snoRNA) and also often referred to as a guide RNA

Guide RNA

Guide RNAs are the RNAs that guide the insertion or deletion of uridine residues into mitochondrial mRNAs in kinetoplastid protists in a process known as RNA editing.-Overview of gRNA-directed editing:...

.

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

Methylation

In the chemical sciences, methylation denotes the addition of a methyl group to a substrate or the substitution of an atom or group by a methyl group. Methylation is a form of alkylation with, to be specific, a methyl group, rather than a larger carbon chain, replacing a hydrogen atom...

 of substrate RNAs. The mouse snoRNA Z19 is orthologous to human U75. U75 is predicted to guide the 2'-O-ribose methylation of 28S ribosomal RNA

Ribosomal RNA

Ribosomal ribonucleic acid is the RNA component of the ribosome, the enzyme that is the site of protein synthesis in all living cells. Ribosomal RNA provides a mechanism for decoding mRNA into amino acids and interacts with tRNAs during translation by providing peptidyl transferase activity...

 (rRNA) residue C4032. In humans U75 shares the same non-protein coding host gene (gas5) with 9 other snoRNAs (U44

Small nucleolar RNA SNORD44

snoRNA U44 is a non-coding RNA molecule which functions in the modification of other small nuclear RNAs . This type of modifiying RNA is usually located in the nucleolus of the eukaryotic cell which is a major site of snRNA biogenesis...

, U47

Small nucleolar RNA SNORD47

SNORD47 is a non-coding RNA molecule which functions in the modification of other small nuclear RNAs . This type of modifiying RNA is usually located in the nucleolus of the eukaryotic cell which is a major site of snRNA biogenesis...

, U74, U76, U77

Small nucleolar RNA SNORD77

U77 belongs to the C/D family of snoRNAs. It is predicted to guide 2'O-ribose methylation of large 28S rRNA subunit at position A1521. The C/D snoRNAs U44, U47, U74, U75, U76, U78, U79, U80 and U81 share the same host gene as U77 ....

, U78

Small nucleolar RNA SNORD78

U78 belongs to the CD family of snoRNAs. It is predicted to guide 2'O-ribose methylation of the large 28S rRNA subunit at position G4593. The snoRNAs U44, U47, U74, U75, U76, U77, U79, U80 and U81, also of the C/D family, share the same host gene with U78 ....

, U79

Small nucleolar RNA SNORD79

snoRNA U79 is a non-coding RNA molecule which functions in the modification of other small nuclear RNAs . This type of modifiying RNA is usually located in the nucleolus of the eukaryotic cell which is a major site of snRNA biogenesis...

, U80 and U81

Small nucleolar RNA SNORD81

U81 is a member of the C/D class of snoRNA which contain the C and D box motifs. U81 acts as a guanine methylation guide and is found in intron 11 of the gas5 gene in mammals....

).