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Postbinding fusion function contributed by a chimeric murine leukemia virus envelope protein
H Nakamura1, A Takeda, T Matano
1AIDS Research Center, National Institute of Infectious Diseases, Musashi-Murayama, Tokyo, Japan.
Archives of Virology
|July 13, 2001
Summary
This study investigated a chimeric Friend murine leukemia virus (FMLV) envelope protein (Env) with human CD4. Results show this CD4-Env chimera retains post-binding fusion capabilities, crucial for viral entry.
Area of Science:
- Virology
- Molecular Biology
- Cell Biology
Background:
- Friend murine leukemia virus (FMLV) envelope protein (Env) mediates viral entry.
- A chimeric FMLV Env was engineered, replacing the receptor-binding domain (RBD) with human CD4.
- The functional integrity of the post-binding fusion activity of this CD4-Env chimera requires investigation.
Purpose of the Study:
- To determine if the CD4-Env chimera retains its post-binding fusion function.
- To assess the role of the CD4-Env chimera in viral-mediated membrane fusion.
- To understand the contribution of the CD4-Env chimera in conjunction with FMLV receptor interactions.
Main Methods:
- Construction of pseudotype murine leukemia viruses (MLVs) bearing the CD4-Env chimera.
- Infectivity assays using NIH 3T3 cells and HeLa cells (with and without FMLV receptor, mCAT1).
- Co-expression studies of CD4-Env with fusion-deficient FMLV Env to induce syncytia formation.
Main Results:
- Pseudotype MLV with CD4-Env alone showed no infectivity.
- Infectivity was observed when CD4-Env was co-expressed with a fusion-deficient FMLV Env in NIH 3T3 cells.
- Syncytia formation occurred in mCAT1-expressing cells, indicating CD4-Env's role in FMLV-mediated fusion.
Conclusions:
- The CD4-Env chimera possesses intact post-binding fusion function.
- The CD4-Env chimera can contribute to membrane fusion in the context of FMLV RBD-mCAT1 interactions.
- This chimeric Env system provides insights into viral fusion mechanisms and receptor engagement.