molecular biology Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physi ...

, SNORD64 (also known as HBII-13) is a

non-coding RNA A non-coding RNA (ncRNA) is a functional RNA molecule that is not translated into a protein. The DNA sequence from which a functional non-coding RNA is transcribed is often called an RNA gene. Abundant and functionally important types of non-c ...

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

small nuclear RNA Small nuclear RNA (snRNA) is a class of small RNA molecules that are found within the splicing speckles and Cajal bodies of the cell nucleus in eukaryotic cells. The length of an average snRNA is approximately 150 nucleotides. They are transcribe ...

s (snRNAs). This type of modifying RNA is located in the

nucleolus The nucleolus (, plural: nucleoli ) is the largest structure in the nucleus of eukaryotic cells. It is best known as the site of ribosome biogenesis, which is the synthesis of ribosomes. The nucleolus also participates in the formation of sig ...

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

small nucleolar RNA In molecular biology, Small nucleolar RNAs (snoRNAs) are a class of small RNA molecules that primarily guide chemical modifications of other RNAs, mainly ribosomal RNAs, transfer RNAs and small nuclear RNAs. There are two main classes of snoRNA, t ...

(snoRNA) and also often referred to as a guide RNA. SNORD64 belongs to the C/D box class of snoRNAs which contain the conserved sequence motifs known as the C box (UGAUGA) and the D box (CUGA). Most of the members of the box C/D family function in directing site-specific 2'-O-

methylation In the chemical sciences, methylation denotes the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These t ...

of substrate RNAs. snoRNA HBII-13 is expressed mainly in the tissues of brain, but is also in the lungs, the kidneys and muscle; however HBII-13 has no identified target RNA. The HBII-13 gene is located in a 460 kb

intron An intron is any nucleotide sequence within a gene that is not expressed or operative in the final RNA product. The word ''intron'' is derived from the term ''intragenic region'', i.e. a region inside a gene."The notion of the cistron .e., gene. ...

of the large paternally-expressed transcription unit ( SNURF-SNRNP-UBE3A AS) along with several other snoRNAs HBII-436, HBII-437, HBII-438A/B and the clusters of HBII-85, HBII-52. This host gene is an antisense transcript to maternally expressed UBE3A gene.

References

External links

* * Small nuclear RNA {{molecular-cell-biology-stub