Nucleolin is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
that in humans is encoded by the ''NCL''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
Gene
The human ''NCL'' gene is located on
chromosome 2
Chromosome 2 is one of the twenty-three pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 2 is the second-largest human chromosome, spanning more than 242 million base pairs and representing almost ei ...
and consists of 14
exon
An exon is any part of a gene that will form a part of the final mature RNA produced by that gene after introns have been removed by RNA splicing. The term ''exon'' refers to both the DNA sequence within a gene and to the corresponding sequence ...
s with 13
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., gen ...
s and spans approximately 11kb. Intron 11 of the ''NCL'' gene encodes a
small nucleolar RNA, termed U20.
Function
Nucleolin is the major nucleolar protein of growing eukaryotic cells. It is found associated with intranucleolar chromatin and pre-ribosomal particles. It induces chromatin decondensation by binding to histone H1. It is thought to play a role in pre-rRNA transcription and ribosome assembly. May play a role in the process of
transcriptional elongation. Binds RNA oligonucleotides with 5'-UUAGGG-3' repeats more tightly than the telomeric single-stranded DNA 5'-TTAGGG-3' repeats.
Nucleolin is also able to act as a transcriptional coactivator with Chicken Ovalbumin Upstream Promoter Transcription Factor II (
COUP-TFII).
Clinical significance
Midkine and
pleiotrophin bind to cell-surface nucleolin as a low affinity receptor. This binding can inhibit HIV infection.
Nucleolin at the cell surface is the receptor for the
respiratory syncytial virus
Respiratory syncytial virus (RSV), also called human respiratory syncytial virus (hRSV) and human orthopneumovirus, is a virus that causes infections of the respiratory tract. It is a negative-sense, single-stranded RNA virus. Its name is derive ...
(RSV)
fusion protein.
Interference with the nucleolinRSV fusion protein interaction has been shown to be therapeutic against RSV infection in cell cultures and animal models.
Interactions
Nucleolin has been shown to
interact with:
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MTDH,
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CSNK2A2,
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Centaurin, alpha 1,
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HuR,
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NPM1
Nucleophosmin (NPM), also known as nucleolar phosphoprotein B23 or numatrin, is a protein that in humans is encoded by the ''NPM1'' gene.
Gene
In humans, the ''NPM1'' gene is located on the long arm of chromosome 5 (5q35). The gene spans 23 kb ...
,
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P53,
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PPP1CB,
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S100A11,
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Sjögren syndrome antigen B,
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TOP1,
and
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Telomerase reverse transcriptase
Telomerase reverse transcriptase (abbreviated to TERT, or hTERT in humans) is a catalytic subunit of the enzyme telomerase, which, together with the telomerase RNA component (TERC), comprises the most important unit of the telomerase complex.
...
.
References
Further reading
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{{PDB Gallery, geneid=4691
Proteins