The CD46 transmembrane domain is required for efficient formation of measles-virus-mediated syncytium

Abstract

Two phosphatidylinositol (PI)-anchored versions of a measles virus (MV) receptor membrane cofactor protein (MCP; CD46) were generated by fusing the extracellular domain of MCP to the decay-accelerating factor (DAF; CD55) or its PI anchor. The PI-anchored forms of MCP expressed on Chinese hamster ovary cells, otherwise non-permissive to MV, conferred a smaller MV cytopathic effect than a wild-type MCP, a Ser/Thr-rich domain-deletion mutant and a cytoplasmic tail-deletion mutant of MCP. Therefore the differences in MV receptor properties between the two PI-anchored and three transmembrane forms were investigated. The PI-anchored forms were predominantly expressed on microvilli as in DAF, whereas the other transmembrane forms were found on intracellular membranes. The PI-anchored forms conferred high MV-binding capacity compared with the transmembrane versions. MV replication was, however, severely suppressed in cells expressing the PI-anchored forms, resulting in ineffective syncytium formation. In contrast, cell-to-cell fusion occurred efficiently after co-transfection of cDNA species encoding MV-H. MV-F and any version of MCP. Thus the PI-anchored forms, despite showing sufficient MV binding and cell-to-cell fusion competence together with MV-H and MV-F, mediate inefficient MV entry or replication, which causes severe suppression of the MV cytopathic effect. A biased receptor distribution on microvilli might participate in the selection of a low MV uptake pathway in the PI-anchored forms of MCP. Taken together, the transmembrane portion of MCP is a critical factor for effective virus-cell fusion and the subsequent MV replication.

Membrane Cofactor Protein (MCP; CD46): Isoform-Specific Tyrosine Phosphorylation

“…Additionally, employing a mouse macrophage cell line transfected with human MCP, Hirano et al observed changes in NO production following stimulation with IFN-␥ that were related to which tail of MCP was expressed (46). Finally, intracellular domains were a critical factor for effective virus-cell fusion and subsequent MV replication (47,48), again suggesting the possibility of a signal transducing event mediated by MCP.…”

CD46 on glial cells can function as a receptor for viral glycoprotein‐mediated cell–cell fusion

“…In many systems tested, CD46 has been demonstrated to mediate this process (Seya et al, 1997;Mori et al, 2003). Albright and colleagues have shown that human adult oligodendrocytes, as well as microglial cells, can be infected when cultured together with HHV-6-infected lymphocytes and that this process results in the formation of multinucleated cells.…”

Functional Modulation of Human Macrophages Through CD46 (Measles Virus Receptor): Production of IL-12 p40 and Nitric Oxide in Association with Recruitment of Protein-Tyrosine Phosphatase SHP-1 to CD46

“…Cells with high expression levels were screened through FACS Vantage using MV-H mAb as a marker. These cells were additionally transfected with MV-F cDNA in some experiments (38). Cells were cultured for 48 h at 37°C in RPMI 1640/10% FCS.…”

“…Various rodent cells (39) were transfected with the MV-H cDNA of NV, those with V451A or I473L single mutations or that of KO using Lipofectamine (38). Vector only was used as the control.…”

“…MV-H and MV-F cDNA of the NV strain placed in pME18s mammalian expression vectors were prepared as described previously (38). Mutations of single nucleotides to generate either V451A or I473L and both were introduced into this NV MV-H-based cDNA by site-directed mutagenesis (QuikChange, Stratagene).…”