Related Experiment Video
Updated: Jun 6, 2026
A Non-random Mouse Model for Pharmacological Reactivation of Mecp2 on the Inactive X Chromosome
Published on: May 22, 2019
The mouse "xenotropic" gammaretroviruses and their XPR1 receptor
1Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892-0460, USA. ckozak@niaid.nih.gov
Abstract:
The xenotropic/polytropic subgroup of mouse leukemia viruses (MLVs) all rely on the XPR1 receptor for entry, but these viruses vary in tropism, distribution among wild and laboratory mice, pathogenicity, strategies used for transmission, and sensitivity to host restriction factors. Most, but not all, isolates have typical xenotropic or polytropic host range, and these two MLV tropism types have now been detected in humans as viral sequences or as infectious virus, termed XMRV, or xenotropic murine leukemia virus-related virus. The mouse xenotropic MLVs (X-MLVs) were originally defined by their inability to infect cells of their natural mouse hosts. It is now clear, however, that X-MLVs actually have the broadest host range of the MLVs. Nearly all nonrodent mammals are susceptible to X-MLVs, and all species of wild mice and several common strains of laboratory mice are X-MLV susceptible. The polytropic MLVs, named for their apparent broad host range, show a more limited host range than the X-MLVs in that they fail to infect cells of many mouse species as well as many nonrodent mammals. The co-evolution of these viruses with their receptor and other host factors that affect their replication has produced a heterogeneous group of viruses capable of inducing various diseases, as well as endogenized viral genomes, some of which have been domesticated by their hosts to serve in antiviral defense.
Insights
Mouse leukemia viruses (MLVs) utilize the XPR1 receptor but exhibit diverse tropisms and host ranges. Xenotropic MLVs (X-MLVs) infect a broad range of mammals, including humans, unlike polytropic MLVs.
Area of Science:
- Virology
- Molecular Biology
- Immunology
Background:
- Xenotropic and polytropic murine leukemia viruses (MLVs) share the XPR1 receptor for cellular entry.
- These MLVs display significant variations in tropism, host range, pathogenicity, transmission, and host restriction factor sensitivity.
- Xenotropic murine leukemia virus-related virus (XMRV) has been detected in humans, highlighting the cross-species potential of MLVs.
Purpose of the Study:
- To elucidate the tropism and host range differences between xenotropic and polytropic MLVs.
- To understand the evolutionary dynamics and host interactions of MLVs.
- To investigate the implications of MLV diversity for disease induction and host defense mechanisms.
Main Methods:
- Comparative analysis of MLV tropism and host range across various mammalian species.
- Investigation of XPR1 receptor usage and its role in MLV entry.
- Examination of viral sequences and infectious virus detection in human populations.
Main Results:
- Xenotropic MLVs (X-MLVs) possess a broader host range than polytropic MLVs, infecting most nonrodent mammals and various mouse species.
- Polytropic MLVs exhibit a more restricted host range compared to X-MLVs.
- MLV evolution has resulted in diverse viral populations with varied pathogenic potentials and host interactions.
Conclusions:
- MLV diversity, driven by co-evolution with host factors, leads to varied disease outcomes.
- Some MLVs have integrated into host genomes, contributing to host antiviral defenses.
- The broad host range of X-MLVs, including human detection, underscores their public health relevance.
