U4atac minor spliceosomal RNA is a

ncRNA 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 ...

which is an essential component of the minor U12-type spliceosome complex. The U12-type spliceosome is required for removal of the rarer class of

eukaryotic Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacte ...

introns (AT-AC, U12-type). U4atac snRNA is proposed to form a base-paired complex with another spliceosomal RNA U6atac via two

stem loop Stem-loop intramolecular base pairing is a pattern that can occur in single-stranded RNA. The structure is also known as a hairpin or hairpin loop. It occurs when two regions of the same strand, usually complementary in nucleotide sequence when ...

regions. These interacting stem loops have been shown to be required for

in vivo Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and ...

splicing. U4atac also contains a 3'

Sm protein In molecular biology, LSm proteins are a family of RNA-binding proteins found in virtually every cellular organism. LSm is a contraction of 'like Sm', because the first identified members of the LSm protein family were the Sm proteins. LSm pro ...

binding site which has been shown to be essential for splicing activity. U4atac is the functional analog of

U4 spliceosomal RNA The U4 small nuclear Ribo-Nucleic Acid (U4 snRNA) is a non-coding RNA component of the major or U2-dependent spliceosome – a eukaryotic molecular machine involved in the splicing of pre-messenger RNA (pre-mRNA). It forms a duplex with U6, an ...

in the major U2-type spliceosomal complex. The

Drosophila ''Drosophila'' () is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species ...

U4atac snRNA has an additional predicted 3' stem loop terminal to the Sm binding site.

Disease

It has been shown that mutations in the U4atac snRNA can cause microcephalic osteodysplastic primordial dwarfism type I (MOPD I), also called Taybi-Linder syndrome (TALS). MOPD I is a developmental disorder that is associated with brain and skeletal abnormalities. It has been shown that the mutations cause defective U12 splicing.

References

External links

* Non-coding RNA Spliceosome RNA splicing {{molecular-cell-biology-stub