The histone 3′ UTR stem-loop is an RNA element involved in nucleocytoplasmic transport of the

histone In biology, histones are highly basic proteins abundant in lysine and arginine residues that are found in eukaryotic cell nuclei and in most Archaeal phyla. They act as spools around which DNA winds to create structural units called nucleosomes ...

mRNAs, and in the regulation of stability and of translation efficiency in the

cytoplasm The cytoplasm describes all the material within a eukaryotic or prokaryotic cell, enclosed by the cell membrane, including the organelles and excluding the nucleus in eukaryotic cells. The material inside the nucleus of a eukaryotic cell a ...

. The

mRNA In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of Protein biosynthesis, synthesizing a protein. mRNA is ...

s of

metazoan Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia (). With few exceptions, animals consume organic material, breathe oxygen, have myocytes and are able to move, can reproduce sexually, and grow from a ho ...

genes lack

polyadenylation Polyadenylation is the addition of a poly(A) tail to an RNA transcript, typically a messenger RNA (mRNA). The poly(A) tail consists of multiple adenosine monophosphates; in other words, it is a stretch of RNA that has only adenine bases. In euka ...

and a

poly-A tail Polyadenylation is the addition of a poly(A) tail to an RNA transcript, typically a messenger RNA (mRNA). The poly(A) tail consists of multiple adenosine monophosphates; in other words, it is a stretch of RNA that has only adenine bases. In euka ...

, instead 3′ end processing occurs at a site between this highly conserved stem-loop and a

purine Purine is a heterocyclic aromatic organic compound that consists of two rings (pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted puri ...

rich region around 20

nucleotide Nucleotides are Organic compound, organic molecules composed of a nitrogenous base, a pentose sugar and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both o ...

s downstream (the histone downstream element, or HDE). The

stem-loop Stem-loops are nucleic acid Biomolecular structure, secondary structural elements which form via intramolecular base pairing in single-stranded DNA or RNA. They are also referred to as hairpins or hairpin loops. A stem-loop occurs when two regi ...

is bound by a 31 kDa stem-loop binding protein (

SLBP Histone RNA hairpin-binding protein or stem-loop binding protein (SLBP) is a protein that in humans is encoded by the ''SLBP'' gene. Species distribution SLBP has been cloned from humans, '' C. elegans'', '' D. melanogaster'', '' X. laevis'', ...

- also termed the histone hairpin binding protein, or HBP). Together with U7 snRNA binding of the HDE, SLBP binding nucleates the formation of the processing complex.

References

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External links

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Transterm page for Histone 3′ stem loop

UTRSite page for Histone 3′UTR stem-loop structure (HSL3)
Cis-regulatory RNA elements {{molecular-cell-biology-stub