Importance of the cytoplasmic tails of the measles virus glycoproteins for fusogenic activity and the generation of recombinant measles viruses.
The generation of replication-competent measles virus (MV) depends on the incorporation of biologically active, fusogenic glycoprotein complexes, which are required for attachment and penetration into susceptible host cells and for direct virus spread by cell-to-cell fusion. Whereas multiple studies have analyzed the importance of the ectodomains of the MV glycoproteins hemagglutinin (H) and fusion protein (F), we have investigated the role of the cytoplasmic tails of the F and H proteins for the formation of fusogenic complexes. Deletions in the cytoplasmic tails of transiently expressed MV glycoproteins were found to have varying effects on receptor binding, fusion, or fusion promotion activity. F tail truncation to only three amino acids did not affect fusion capacity. In contrast, truncation of the H cytoplasmic tail was limited. H protein mutants with cytoplasmic tails of <14 residues no longer supported F-mediated cell fusion, predominantly due to a decrease in surface expression and receptor binding. This indicates that a minimal length of the H protein tail of 14 amino acids is required to ensure a threshold local density to have sufficient accumulation of fusogenic H-F complexes. By using reverse genetics, a recombinant MV with an F tail of three amino acids (rMV-FcDelta30), as well as an MV with an H tail of 14 residues (rMV-HcDelta20), could be rescued, whereas generation of viruses with shorter H tails failed. Thus, glycoprotein truncation does not interfere with the successful generation of recombinant MV if fusion competence is maintained.
Moll
Markus
M
Institute of Virology, Philipps University of Marburg, Marburg, Germany.
Klenk
Hans-Dieter
HD
Maisner
Andrea
A
D000595:Amino Acid Sequence; D000818:Animals; D002459:Cell Fusion; D002460:Cell Line; D002522:Chlorocebus aethiops; D015726:Giant Cells; D006389:Hemagglutinins, Viral / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D006801:Humans; D008459:Measles virus / Q000737:chemistry / Q000235:genetics / Q000472:pathogenicity*; D008561:Membrane Fusion; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011995:Recombination, Genetic; D014709:Vero Cells; D014760:Viral Fusion Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D014779:Virus Replication
D006389:Hemagglutinins, Viral; D014760:Viral Fusion Proteins; C032397:hemagglutinin protein G, measles virus