Mumps virus
Encyclopedia
Mumps virus
is the causative agent of mumps
, a well-known common childhood disease characterised by swelling of the parotid glands and other epithelial tissues, causing high morbidity and in some cases more serious complications such as deafness. Natural infection is currently restricted to humans and the virus is transmitted by direct contact, droplet spread, or contaminated objects.
It is considered a vaccine
-preventable disease, although significant outbreaks have occurred in recent years in developed countries such as America, in areas of poor vaccine uptake. These have allowed the further evaluation and ennumeration of its efficacy (~75-85% after two doses of MMR
).
Mumps virus belongs to the genus Rubulavirus
in the family Paramyxoviridae and is seen to have a roughly spherical, enveloped morphology of about 200 nm in diameter. It contains a linear, single-stranded molecule of negative-sense RNA
15,384 nucleotides long.
molecules, and nucleic acid
. It is dotted with large 'spikes' made up of protein that enable it to gain entry to host cells
. Inside lies a core of a single, long molecule of RNA wrapped up in protein that is released into the cell.
These particles consist of what is known as a ribonucleoprotein (RNP) complex: a single-stranded, linear RNA
genome
coated by nucleocapsid proteins (NP) in association with an RNA polymerase
complex of both large (L) and phosphoprotein (P) subunits. It has been estimated that over 2,000 such NP molecules coat the genome along with about 250 P and 25 L molecules.
This RNP structure interacts with the viral envelope
via matrix (M) proteins that are evenly distributed around the virion. The envelope, a lipid bilayer
derived from the host-cell plasma membrane, harbours multiple copies of a number of glycoproteins required for virus entry and exit: haemagluttin-neuraminidase (HN), fusion (F), and the small hydrophobic (SH) protein.
This molecular assembly of protein, RNA, and lipids allows a single virus to bind to and infect specific cells and replicate itself and finally exit the cell to be transmitted to the next susceptible host.
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...
is the causative agent of mumps
Mumps
Mumps is a viral disease of the human species, caused by the mumps virus. Before the development of vaccination and the introduction of a vaccine, it was a common childhood disease worldwide...
, a well-known common childhood disease characterised by swelling of the parotid glands and other epithelial tissues, causing high morbidity and in some cases more serious complications such as deafness. Natural infection is currently restricted to humans and the virus is transmitted by direct contact, droplet spread, or contaminated objects.
It is considered a vaccine
Vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
-preventable disease, although significant outbreaks have occurred in recent years in developed countries such as America, in areas of poor vaccine uptake. These have allowed the further evaluation and ennumeration of its efficacy (~75-85% after two doses of MMR
MMR
MMR has numerous meanings.In science and medicine:* Measles, mumps and rubella, as in MMR vaccine* DNA mismatch repair, a genetic repair pathway* Mass miniature radiography, a screening X-ray photofluorography technique* Maternal Mortality Ratio...
).
Mumps virus belongs to the genus Rubulavirus
Rubulavirus
Rubulavirus is a genus of the Paramyxoviridae family of infectious viruses. The genus includes the mumps virus and parainfluenza type 2, 4a and 4b viruses.-External links:* http://www.biology-online.org/dictionary/Rubulavirus*...
in the family Paramyxoviridae and is seen to have a roughly spherical, enveloped morphology of about 200 nm in diameter. It contains a linear, single-stranded molecule of negative-sense RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
15,384 nucleotides long.
Structure
The Mumps virus is a roughly spherical particle made up of concentric layers of fatty lipids, large proteinProtein
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...
molecules, and 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...
. It is dotted with large 'spikes' made up of protein that enable it to gain entry to host cells
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
. Inside lies a core of a single, long molecule of RNA wrapped up in protein that is released into the cell.
Basic Morphology
Electron microscopy (EM) revealed that Mumps virus (MuV), like other members of the Paramyxoviridae, has an enveloped virion of roughly spherical or pleiomorphic (variable) shape. Paramyxovirus particles can have sizes ranging from 120 – 450 nm in diameter.These particles consist of what is known as a ribonucleoprotein (RNP) complex: a single-stranded, linear RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
coated by nucleocapsid proteins (NP) in association with an 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...
complex of both large (L) and phosphoprotein (P) subunits. It has been estimated that over 2,000 such NP molecules coat the genome along with about 250 P and 25 L molecules.
This RNP structure interacts with the viral envelope
Viral envelope
Many viruses have viral envelopes covering their protein capsids. The envelopes typically are derived from portions of the host cell membranes , but include some viral glycoproteins. Functionally, viral envelopes are used to help viruses enter host cells...
via matrix (M) proteins that are evenly distributed around the virion. The envelope, a lipid bilayer
Lipid bilayer
The lipid bilayer is a thin membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around cells. The cell membrane of almost all living organisms and many viruses are made of a lipid bilayer, as are the membranes surrounding the cell nucleus...
derived from the host-cell plasma membrane, harbours multiple copies of a number of glycoproteins required for virus entry and exit: haemagluttin-neuraminidase (HN), fusion (F), and the small hydrophobic (SH) protein.
This molecular assembly of protein, RNA, and lipids allows a single virus to bind to and infect specific cells and replicate itself and finally exit the cell to be transmitted to the next susceptible host.