Efficient assembly of an HIV-1/MLV Gag-chimeric virus in murine cells.
In human cells infected by HIV type 1 (HIV-1), the viral Gag protein directs the assembly of nascent viral particles at the plasma membrane. In murine cells, HIV-1 Gag fails to reach the plasma membrane and instead forms nonfunctional intracellular aggregates. The viral determinants of this species incompatibility are previously undefined. To address this problem, we replaced a region of HIV-1 Gag known to direct its localization, the matrix (MA) domain, with functionally homologous regions from Moloney murine leukemia virus (MLV), a murine retrovirus. An HIV-1 clone carrying such a chimeric Gag protein, designated murine HIV (MHIV), assembled more efficiently than nonchimeric HIV-1 and restored plasma membrane localization of Gag in murine cells. Increased efficiency of viral assembly in murine cells was observed from MHIV constructs carrying MLV MA in place of HIV-1 MA. Efficient processing of the HIV-1 capsid protein from the chimeric Gag polyprotein and subsequent infectivity of MHIV required the presence of MLV p12 in addition to MLV MA. These findings strongly suggest that the HIV-1 MA domain of HIV-1 Gag is responsible for the assembly defect in mouse cells. Although these MHIV do not recruit native HIV-1 Env efficiently, they are capable of single-round infection when produced by high-efficiency transfection of human 293 cells and provided with an HIV-1 Env lacking its cytoplasmic tail. With further adaptation, this chimeric MHIV approach may provide the basis for creating an infectious mouse model for HIV/AIDS.
Chen
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BK
Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Nine Cambridge Center, Cambridge, MA 02142, USA. benchen@wi.mit.edu
Rousso
I
I
Shim
S
S
Kim
P S
PS
D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002460:Cell Line; D002678:Chimera; D017931:DNA Primers; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D015683:Gene Products, gag / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics / Q000502:physiology*; D009052:Leukemia Virus, Murine / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008856:Microscopy, Fluorescence; D019065:Virus Assembly
D017931:DNA Primers; D015683:Gene Products, gag