mLv

Murine leukemia virus (MLV) is a retrovirus in the family Retroviridae, genus Gammaretrovirus. It infects mice and related species and has been used extensively in biomedical research as a model of viral oncogenesis and as a backbone for retroviral vectors in gene delivery. MLV exists as several strains distinguished by host range, including ecotropic, xenotropic, and polytropic variants. Ecotropic MLVs infect mouse cells and typically use the mCAT-1 receptor; xenotropic and polytropic strains can infect cells from other species and show broader host range, though receptor use varies by strain. In mice, infection can lead to diseases such as thymic lymphoma and leukemia, reflecting the virus’s oncogenic potential in susceptible strains, though most modern laboratory MLV strains are modified to reduce pathogenicity for research use.

In biotechnology, MLV-based retroviral vectors are common tools for delivering genetic material to dividing cells. They integrate their genome into the host cell DNA, enabling stable gene expression, but insertional mutagenesis can disrupt host genes or regulatory elements, a safety concern that has influenced vector design and clinical use. Modern gene therapy has largely shifted toward lentiviral vectors or non-integrating approaches to mitigate risks.

Researchers use MLVs as a model of retroviral replication and pathogenesis, and as a genetic tool in basic and translational studies. Handling requires appropriate biosafety measures and institutional oversight.