Ribonucleoprotein
Encyclopedia
Ribonucleoprotein is a nucleoprotein
that contains RNA
, i.e. it is an association that combines ribonucleic acid and protein
together. A few known examples include the ribosome
, the enzyme telomerase
, vault ribonucleoproteins
, and small nuclear RNPs (snRNP
s), which are implicated in pre-mRNA splicing
and are among the main components of the nucleolus
. 'RNP' can also refer to ribonucleoprotein particles
, distinct intracellular foci for post-transcriptional regulation
.
RNP in snRNPs has an RNA-binding motif
in its RNA-binding protein. Aromatic
amino acid
residues in this motif result in stacking interactions with RNA. Lysine
residues in the helical
portion of RNA-binding proteins help to stabilize interactions with nucleic acids. This nucleic acid binding is strengthened by electrostatic
attraction between the positive lysine side chain
s and the negative nucleic acid
phosphate
backbones.
RNPs play an important role in influenzavirus A
replication
. The viral
RNA
is transcribed
into mRNAs
by the RNA polymerase
attached to the RNPs.
and are also detected in nearly 40% of Lupus erythematosus
patients. Two types of anti-RNP antibodies are closely related to Sjögren's syndrome
: SS-A (Ro) and SS-B (La).
Nucleoprotein
A nucleoprotein is any protein that is structurally associated with nucleic acid .Many viruses harness this protein, and they are known for being host-specific...
that contains RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
, i.e. it is an association that combines ribonucleic acid and protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
together. A few known examples include the ribosome
Ribosome
A ribosome is a component of cells that assembles the twenty specific amino acid molecules to form the particular protein molecule determined by the nucleotide sequence of an RNA molecule....
, the enzyme telomerase
Telomerase
Telomerase is an enzyme that adds DNA sequence repeats to the 3' end of DNA strands in the telomere regions, which are found at the ends of eukaryotic chromosomes. This region of repeated nucleotide called telomeres contains non-coding DNA material and prevents constant loss of important DNA from...
, vault ribonucleoproteins
Vault (organelle)
The vault or vault cytoplasmic ribonucleoprotein is a eukaryotic organelle whose function is not fully understood. Discovered and successfully isolated by cell biologist Nancy Kedersha and biochemist Leonard Rome of the UCLA School of Medicine in the 1980s, vaults are cytoplasmic organelles which...
, and small nuclear RNPs (snRNP
SnRNP
snRNPs , or small nuclear ribonucleoproteins, are RNA-protein complexes that combine with unmodified pre-mRNA and various other proteins to form a spliceosome, a large RNA-protein molecular complex upon which splicing of pre-mRNA occurs...
s), which are implicated in pre-mRNA splicing
RNA splicing
In molecular biology and genetics, splicing is a modification of an RNA after transcription, in which introns are removed and exons are joined. This is needed for the typical eukaryotic messenger RNA before it can be used to produce a correct protein through translation...
and are among the main components of 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...
. 'RNP' can also refer to ribonucleoprotein particles
Ribonucleoprotein Particle
A ribonucleoprotein particle or RNP is a complex formed between RNA and RNA-binding proteins . The term 'RNP foci' is also used to denote an intracellular compartment involved in processing of RNA transcripts.- RNA/RBP complexes :...
, distinct intracellular foci for post-transcriptional regulation
Post-transcriptional regulation
Post-transcriptional regulation is the control of gene expression at the RNA level, therefore between the transcription and the translation of the gene...
.
RNP in snRNPs has an RNA-binding motif
Structural motif
In a chain-like biological molecule, such as a protein or nucleic acid, a structural motif is a supersecondary structure, which appears also in a variety of other molecules...
in its RNA-binding protein. Aromatic
Aromaticity
In organic chemistry, Aromaticity is a chemical property in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone. The earliest use of the term was in an article by August...
amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
residues in this motif result in stacking interactions with RNA. Lysine
Lysine
Lysine is an α-amino acid with the chemical formula HO2CCH4NH2. It is an essential amino acid, which means that the human body cannot synthesize it. Its codons are AAA and AAG....
residues in the helical
Helix
A helix is a type of smooth space curve, i.e. a curve in three-dimensional space. It has the property that the tangent line at any point makes a constant angle with a fixed line called the axis. Examples of helixes are coil springs and the handrails of spiral staircases. A "filled-in" helix – for...
portion of RNA-binding proteins help to stabilize interactions with nucleic acids. This nucleic acid binding is strengthened by electrostatic
Electrostatics
Electrostatics is the branch of physics that deals with the phenomena and properties of stationary or slow-moving electric charges....
attraction between the positive lysine side chain
Side chain
In organic chemistry and biochemistry, a side chain is a chemical group that is attached to a core part of the molecule called "main chain" or backbone. The placeholder R is often used as a generic placeholder for alkyl group side chains in chemical structure diagrams. To indicate other non-carbon...
s and the negative nucleic acid
Nucleic acid
Nucleic acids are biological molecules essential for life, and include DNA and RNA . Together with proteins, nucleic acids make up the most important macromolecules; each is found in abundance in all living things, where they function in encoding, transmitting and expressing genetic information...
phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
backbones.
RNPs play an important role in influenzavirus A
Influenzavirus A
Influenza A virus causes influenza in birds and some mammals and is the only species of Influenzavirus A. Influenzavirus A is a genus of the Orthomyxoviridae family of viruses. Strains of all subtypes of influenza A virus have been isolated from wild birds, although disease is uncommon...
replication
Self-replication
Self-replication is any behavior of a dynamical system that yields construction of an identical copy of that dynamical system. Biological cells, given suitable environments, reproduce by cell division. During cell division, DNA is replicated and can be transmitted to offspring during reproduction...
. The viral
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
is transcribed
Transcription (genetics)
Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...
into mRNAs
Messenger RNA
Messenger RNA is a molecule of RNA encoding a chemical "blueprint" for a protein product. mRNA is transcribed from a DNA template, and carries coding information to the sites of protein synthesis: the ribosomes. Here, the nucleic acid polymer is translated into a polymer of amino acids: a protein...
by the RNA polymerase
RNA polymerase
RNA polymerase is an enzyme that produces RNA. In cells, RNAP is needed for constructing RNA chains from DNA genes as templates, a process called transcription. RNA polymerase enzymes are essential to life and are found in all organisms and many viruses...
attached to the RNPs.
Anti-RNP antibodies
Anti-RNP antibodies are autoantibodies associated with mixed connective tissue diseaseMixed connective tissue disease
In medicine, mixed connective tissue disease , commonly abbreviated as MCTD, is an autoimmune disease, in which the body's defense system attacks itself. It was characterized in 1972....
and are also detected in nearly 40% of Lupus erythematosus
Lupus erythematosus
Lupus erythematosus is a category for a collection of diseases with similar underlying problems with immunity . Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs...
patients. Two types of anti-RNP antibodies are closely related to Sjögren's syndrome
Sjögren's syndrome
Sjögren's syndrome , also known as "Mikulicz disease" and "Sicca syndrome", is a systemic autoimmune disease in which immune cells attack and destroy the exocrine glands that produce tears and saliva....
: SS-A (Ro) and SS-B (La).
List of RNPs
This is a (partial) list of ribonucleoprotein families:- hnRNP
- RibosomeRibosomeA ribosome is a component of cells that assembles the twenty specific amino acid molecules to form the particular protein molecule determined by the nucleotide sequence of an RNA molecule....
- snRNPSnRNPsnRNPs , or small nuclear ribonucleoproteins, are RNA-protein complexes that combine with unmodified pre-mRNA and various other proteins to form a spliceosome, a large RNA-protein molecular complex upon which splicing of pre-mRNA occurs...
- Signal recognition particleSignal recognition particleThe signal recognition particle is an abundant, cytosolic, universally conserved ribonucleoprotein that recognizes and targets specific proteins to the endoplasmic reticulum in eukaryotes and the plasma membrane in prokaryotes....
(a protein coated ribozymeRibozymeA ribozyme is an RNA molecule with a well defined tertiary structure that enables it to catalyze a chemical reaction. Ribozyme means ribonucleic acid enzyme. It may also be called an RNA enzyme or catalytic RNA. Many natural ribozymes catalyze either the hydrolysis of one of their own...
) - TelomeraseTelomeraseTelomerase is an enzyme that adds DNA sequence repeats to the 3' end of DNA strands in the telomere regions, which are found at the ends of eukaryotic chromosomes. This region of repeated nucleotide called telomeres contains non-coding DNA material and prevents constant loss of important DNA from...