Mouse Mammary Tumor Virus: Difference between revisions
Sanfilippop (talk | contribs) |
Sanfilippop (talk | contribs) No edit summary |
||
| Line 1: | Line 1: | ||
{{Viral Biorealm Family}} | {{Viral Biorealm Family}} | ||
[[Image: | [[Image:Mmtv virus.jpg\|thumb|200px|right|MMTV particles [http://www.abc.net.au/science/news/stories/s927415.htm].]] | ||
<br><br> | <br><br> | ||
==Baltimore Classification== | ==Baltimore Classification== | ||
Revision as of 18:53, 16 September 2008
A Viral Biorealm page on the family Mouse Mammary Tumor Virus
Baltimore Classification
Group VI. RNA Reverse Transcribing Viruses (Retroviruses)
Higher order categories
Order: Unassigned
Family: Retroviridae
Subfamily: Orthoretrovirinae
Genus: Betaretrovirus
Description and Significance
Mouse Mammary Tumor Virus (MMTV)was reported for the first time in 1933 by the Jackson Memorial Laboratory. It was initially identified by studying inbred mouse strains characterized by a high incidence of mammary tumor.
continues
Genome Structure
Genome structure
continues
Virion Structure of MMTV
The MMTV virion is a B-type particle containing a genomic RNA dimer, encapsidated by NC proteins in the form of a helical nucleoprotein (RNP). Surrounding the genomic material is an apparently icosahedral capsid, formed by CA proteins. The capsid is bound to the envelope by the matrix protein MA. Finally, the viral envelope is characterized by several spikes, composed of a transmembrane protein and a surface protein [enc virology].
Reproductive Cycle of MMTV
MMTV can be transferred through either an endogenous (vertical) or exogenous (horizontal) pathway.
The endogenous pathway occurs when the virus is transferred from mother to progeny as a provirus, inserted in the host DNA. In a typical strain there are as many as 14 proviruses, most of which are no longer functional. The proviruses are transmitted in mendelian fashion.
The exogenous pathway occurs through transfer of the viral particles, from mother to progeny, in the milk. Other body fluids might also contains low levels of MMTV particles, but milk remains the main route of exogenous transfer of the virions.
Not much is known about the entry and exit of MMTV from the host cell. The host cell receptor that seems to be the attachment site for MMTV is the surface glycoprotein gp52. The viral protein MTVR-1 is believed to attach to gp52 and trigger the entry of the virion. Once the viral particle crosses the plasma membrane, it loses its capsid and retrotranscription of the viral genome begins. Once the provirus is synthesized, it migrates to the nucleus were it integrates in the host genome. If the provirus is integrated next to an oncogene, tumorigenesis may occur. Transcription of the viral genome is particularly active in the mammary glands and estrogen acts as an inducer of viral genes transcription.
Viral Ecology & Pathology
pathology.
cancer
info
References
references Page authored for BIOL 375 Virology, September 2008
