Mouse mammary tumor virus

Mouse Mammary Tumor Virus

Diagram of the MMTV genome

The Mouse Mammary Tumor Virus (MMTV) is a retrovirus that is known to cause breast cancer in mice. It is a member of the Betaretrovirus genus and is one of the most studied animal models for understanding the mechanisms of oncogenesis in mammals.

History

MMTV was first identified in the early 20th century when researchers observed that certain strains of mice had a high incidence of mammary tumors. Subsequent studies revealed that these tumors were associated with a transmissible agent, which was later identified as a virus.

Structure and Genome

MMTV is an enveloped virus with a single-stranded RNA genome. The genome of MMTV is approximately 9 kilobases in length and encodes several proteins essential for viral replication and pathogenesis. The genome includes the gag, pol, and env genes, as well as regulatory sequences such as the long terminal repeat (LTR).

Life Cycle

The life cycle of MMTV begins with the infection of mammary epithelial cells. The virus enters the cell by binding to a specific receptor on the cell surface. Once inside, the viral RNA is reverse transcribed into DNA by the viral reverse transcriptase enzyme. This DNA is then integrated into the host cell's genome, where it can be transcribed and translated to produce new viral particles.

Pathogenesis

MMTV is known to cause mammary tumors in mice by integrating into the host genome and activating oncogenes. The virus can also modulate the host's immune response, allowing for persistent infection and tumor development. The study of MMTV has provided significant insights into the role of viruses in cancer development.

Transmission

MMTV is primarily transmitted through the milk of infected female mice to their offspring. This mode of transmission ensures that the virus is passed from one generation to the next, maintaining its presence in mouse populations.

Research and Implications

Research on MMTV has been instrumental in understanding the mechanisms of viral oncogenesis. It has also provided a model for studying breast cancer in humans, although the direct relevance of MMTV to human breast cancer remains a topic of investigation.

Related pages

• Retrovirus
• Oncogenesis
• Breast cancer
• Viral replication