Characterization of cell fusion in XC cells induced by Suncus murinus mammary tumor virus.
Syncytium formation in a rat tumor cell line (XC) induced by Suncus murinus mammary tumor virus (Sm-MTV) was studied. Multinucleate giant cells containing 20-30 nuclei were formed in a monolayer of XC cells by cocultivation with X-ray-irradiated Sm-MTV producing cells (Sm-MT-1). By fluorescent antibody staining. Sm-MTV antigens were demonstrated in the cytoplasm of syncytia, and budding particles and intracytoplasmic A particles were found in syncytial giant cells by electron microscopy. Cell-free supernatant of Sm-MT-1 was capable of inducing syncytia at a much lower incidence than cocultivation of Sm-MT-1 cells. Syncytium formation was completely inhibited when anti-Sm-MTV bovine serum was added to the coculture medium. Pretreatment of XC cells with actinomycin-D caused a partial reduction of Sm-MTV-induced cell fusion, but syncytium formation did occur at a reduced rate even when cellular RNA synthesis was completely inhibited. Dexamethasone increased virus production in Sm-MT-1 cells, resulting in the enhancement of Sm-MTV mediated syncytium formation. Sm-MTV was found to have a unique characteristic of cell fusion activity on XC cells with striking enhancement by dexamethasone.
Department of Pathology, Nagoya University School of Medicine, Japan.
T
T
Yokoi
A
A
Aoyama
S
S
Nagayoshi
Y
Y
Tsutsui
S
S
Saga
K
K
Iida
M
M
Takahashi
Y
Y
Kimura
M
M
Hoshino
D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology / Q000302:isolation & purification; D002417:Cattle; D002459:Cell Fusion / Q000187:drug effects; D003609:Dactinomycin / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D015674:Mammary Neoplasms, Animal / Q000382:microbiology; D009858:Oncogenic Viruses / Q000302:isolation & purification / Q000502:physiology*; D012313:RNA / Q000096:biosynthesis; D051381:Rats; D012190:Retroviridae / Q000302:isolation & purification / Q000502:physiology*; D012788:Shrews / Q000382:microbiology; D014407:Tumor Cells, Cultured; D014779:Virus Replication / Q000187:drug effects
D000914:Antibodies, Viral; D003609:Dactinomycin; D012313:RNA; D003907:Dexamethasone