1992/04/01 by Maria da Conceição PEDROSO DE LIMA, Maria C. Pedroso de Lima, João RAMALHO‐SANTOS +9
Biochemistry, Genetics and Molecular Biology · Chemistry · Immunology and Microbiology · Medicine · #Biochemistry #Biology #Biophysics #Cell #Cell fusion #Chemistry #Fusion #Glycoprotein #HIV Research and Treatment #Kinetics #Lipid bilayer fusion #Liposome #Membrane #Sendai virus #Viral envelope #Virology and Viral Diseases #Virus-based gene therapy research
paper · pdf · doi:10.1111/j.1432-1033.1992.tb16766.x
openalex publication_date 1992/04/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
We have studied the fusion activity of Sendai virus, a lipid-enveloped paramyxovirus, towards a line of adherent cells designated PC-12. Fusion was monitored by the dequenching of octadecyl-rhodamine, a fluorescent non-exchangeable probe. The results were analysed with a mass action kinetic model which could explain and predict the kinetics of virus-cell fusion. When the temperature was lowered from 37 degrees C to 25 degrees C, a sharp inhibition of the fusion process was observed, probably reflecting a constraint in the movement of viral glycoproteins at low temperatures. The rate constants of adhesion and fusion were reduced 3.5-fold and 7-fold, respectively, as the temperature was lowered from 37 degrees C to 25 degrees C. The fusion process seemed essentially pH-independent, unlike the case of liposomes and erythrocyte ghosts. Preincubation of the virus in the absence of target cell membranes at neutral and alkaline pH (37 degrees C, 30 min) did not affect the fusion process. However, a similar preincubation of the virus at pH = 5.0 resulted in marked, though slow, inhibition in fusion with the fusion rate constant being reduced 8-fold. Viral preincubation for 5 min in the same acidic conditions yielded a mild inhibition of fusogenic activity, while preincubation in the cold (4 degrees C, 30 min) did not alter viral fusion activity. These acid-induced inhibitory effects could not be fully reversed by further viral preincubation at pH = 7.4 (37 degrees C, 30 min). Changes in internal pH as well as endocytic activity of PC-12 cells had small effect on the fusion process, thus indicating that Sendai virus fuses primarily with the plasma membranes.