Murid herpesvirus 68 is an isolate of Murid herpesvirus 4

Murid herpesvirus 4

Murid herpesvirus 4 is a virus in the genus Rhadinovirus. It is a member of the subfamily Gammaherpesvirinae in the family Herpesviridae...

 which is a virus

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...

 in the genus Rhadinovirus

Rhadinovirus

Rhadinoviruses are a genus of herpesviruses that include the Human herpesvirus 8 , also known as Kaposi's sarcoma-associated herpesvirus , which causes Kaposi's sarcoma, primary effusion lymphoma and multicentric Castleman's disease. Other names for the Rhadinovirus genus include Rhadinoviridae...

. It is a member of the subfamily Gammaherpesvirinae

Gammaherpesvirinae

Gammaherpesvirinae is a subfamily of Herpesviridae distinguished by reproducing at a more variable rate than other subfamilies of Herpesviridae...

 in the family of Herpesviridae

Herpesviridae

The Herpesviridae are a large family of DNA viruses that cause diseases in animals, including humans. The members of this family are also known as herpesviruses. The family name is derived from the Greek word herpein , referring to the latent, recurring infections typical of this group of viruses...

. MHV-68 serves as a model for study of human gammaherpesviruses which cause significant human disease including B-cell lymphoma

B-cell lymphoma

The B-cell lymphomas are types of lymphoma affecting B cells. Lymphomas are "blood cancers" in the lymph glands. They develop more frequently in older adults and in immunocompromised individuals ....

 and Kaposi's sarcoma

Kaposi's sarcoma

Kaposi's sarcoma is a tumor caused by Human herpesvirus 8 , also known as Kaposi's sarcoma-associated herpesvirus . It was originally described by Moritz Kaposi , a Hungarian dermatologist practicing at the University of Vienna in 1872. It became more widely known as one of the AIDS defining...

. The WUMS strain

Strain (biology)

In biology, a strain is a low-level taxonomic rank used in three related ways.-Microbiology and virology:A strain is a genetic variant or subtype of a micro-organism . For example, a "flu strain" is a certain biological form of the influenza or "flu" virus...

 of MHV-68 was fully sequenced and annotated in 1997
, and the necessity of most of its genes in viral replication was characterized by random transposon

Transposon

Transposable elements are sequences of DNA that can move or transpose themselves to new positions within the genome of a single cell. The mechanism of transposition can be either "copy and paste" or "cut and paste". Transposition can create phenotypically significant mutations and alter the cell's...

 mutagenesis

Mutagenesis

Mutagenesis is a process by which the genetic information of an organism is changed in a stable manner, resulting in a mutation. It may occur spontaneously in nature, or as a result of exposure to mutagens. It can also be achieved experimentally using laboratory procedures...

 study
.

MHV-68 surface proteins

Alpha

Alphaherpesvirinae

Alphaherpesvirinae is a subfamily of Herpesviridae primarily distinguished by reproducing more quickly than other subfamilies of Herpesviridae. In animal virology the most important herpesviruses belong to the Alphaherpesvirinae...

-, beta

Betaherpesvirinae

Betaherpesvirinae is a subfamily of Herpesviridae distinguished by reproducing less quickly than other subfamilies of Herpesviridae.Betaherpesvirinae establish latency in leukocytes...

-, and gammaherpesviruses

Gammaherpesvirinae

Gammaherpesvirinae is a subfamily of Herpesviridae distinguished by reproducing at a more variable rate than other subfamilies of Herpesviridae...

 display a heterodimer composed of glycoprotein

Glycoprotein

Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...

 H (gH) and glycoprotein L (gL) on their envelopes

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...

. This receptor

Receptor (biochemistry)

In biochemistry, a receptor is a molecule found on the surface of a cell, which receives specific chemical signals from neighbouring cells or the wider environment within an organism...

 is involved in the cell-to-cell transmission of the virus. Glycoprotein H has two conformations

Protein structure

Proteins are an important class of biological macromolecules present in all organisms. Proteins are polymers of amino acids. Classified by their physical size, proteins are nanoparticles . Each protein polymer – also known as a polypeptide – consists of a sequence formed from 20 possible L-α-amino...

. Glycoprotein L is a chaperone protein which assures that gH takes on the correct conformation. When herpesviruses lack gL, gH misfolds. When alpha- or betaherpesviruses lack gL, they are noninfectious. When Murine Gammaherpesvirus 68 lacks gL, it remains infectious but is less able to bind to fibroblasts and epithelial cells.

The open reading frame

Open reading frame

In molecular genetics, an open reading frame is a DNA sequence that does not contain a stop codon in a given reading frame.Normally, inserts which interrupt the reading frame of a subsequent region after the start codon cause frameshift mutation of the sequence and dislocate the sequences for stop...

 M7 of the MHV-68 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....

 encodes for the surface receptor glycoprotein 150 (gp150). It is homologous

Homology (biology)

Homology forms the basis of organization for comparative biology. In 1843, Richard Owen defined homology as "the same organ in different animals under every variety of form and function". Organs as different as a bat's wing, a seal's flipper, a cat's paw and a human hand have a common underlying...

 to the Epstein-Barr virus

Epstein-Barr virus

The Epstein–Barr virus , also called human herpesvirus 4 , is a virus of the herpes family and is one of the most common viruses in humans. It is best known as the cause of infectious mononucleosis...

 membrane antigen

Antigen

An antigen is a foreign molecule that, when introduced into the body, triggers the production of an antibody by the immune system. The immune system will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader. These invaders can be molecules such as...

 gp350/220. MHV-68 is more closely related to the Kaposi's Sarcoma-associated herpesvirus (KSHV) than it is to the Epstein-Barr virus

Epstein-Barr virus

The Epstein–Barr virus , also called human herpesvirus 4 , is a virus of the herpes family and is one of the most common viruses in humans. It is best known as the cause of infectious mononucleosis...

. Glycoprotein K8.1 is the KSHV homolog of MHV-68 gp150. MHV-68 is a very close relative of MHV-72. The MHV-68 M7 gene differs from the corresponding MHV-72 gene by five point mutations which alter four codons. Glycoprotein 150 allows MHV-68 to bind to B-cells.