| Murid herpesvirus 68 | |
|---|---|
| Virus classification | |
| Group: | Group I (dsDNA) |
| Family: | Herpesviridae |
| Subfamily: | Gammaherpesvirinae |
| Genus: | Rhadinovirus |
| Species: | Murid herpesvirus 4 |
| Subspecies: | Murid herpesvirus 68 (MHV-68) |
Murid herpesvirus 68 (MHV-68) is an isolate of Murid herpesvirus 4 which is a virus in the genus Rhadinovirus. It is a member of the subfamily Gammaherpesvirinae in the family of Herpesviridae. MHV-68 serves as a model for study of human gammaherpesviruses which cause significant human disease including B-cell lymphoma and Kaposi's sarcoma. The WUMS strain of MHV-68 was fully sequenced and annotated in 1997 ,[1] and the necessity of most of its genes in viral replication was characterized by random transposon mutagenesis study .[2]
Alpha-, beta-, and gammaherpesviruses display a heterodimer composed of glycoprotein H (gH) and glycoprotein L (gL) on their envelopes. This receptor is involved in the cell-to-cell transmission of the virus. Glycoprotein H has two conformations. 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.[3]
The open reading frame M7 of the MHV-68 genome encodes for the surface receptor glycoprotein 150 (gp150). It is homologous to the Epstein-Barr virus membrane antigen gp350/220.[4] MHV-68 is more closely related to the Kaposi's Sarcoma-associated herpesvirus (KSHV) than it is to the Epstein-Barr virus. Glycoprotein K8.1 is the KSHV homolog of MHV-68 gp150.[5] 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.[4] Glycoprotein 150 allows MHV-68 to bind to B-cells.[5]