A single amino acid substitution in a hydrophobic domain causes temperature-sensitive cell-surface transport of a mutant viral glycoprotein.

AUTOR(ES)

Gallione, C J

RESUMO

DNA sequences were determined for three cDNA clones encoding vesicular stomatitis virus glycoproteins from the tsO45 mutant (which encodes a glycoprotein that exhibits temperature-sensitive cell-surface transport), the wild-type parent strain, and a spontaneous revertant of tsO45. The DNA sequence analysis showed that as many as three amino acid changes could be responsible for the transport defect. By recombining the cDNA clones in vitro and expressing the recombinants in COS cells, we were able to trace the critical lesion in tsO45 to a single substitution of a polar amino acid (serine) for a hydrophobic amino acid (phenylalanine) in a hydrophobic domain. We suggest that this nonconservative substitution may block protein transport by causing protein denaturation at the nonpermissive temperature. Comparison of the predicted glycoprotein sequences from two vesicular stomatitis virus strains suggests a possible basis for the differential carbohydrate requirement in transport of the two glycoproteins.

Documentos Relacionados

• Secretion and cell-surface growth are blocked in a temperature-sensitive mutant of Saccharomyces cerevisiae.
• A single-amino-acid substitution eliminates the stringent carbohydrate requirement for intracellular transport of a viral glycoprotein.
• A mammalian temperature-sensitive mutation affecting G1 progression results from a single amino acid substitution in asparagine synthetase.
• Incorporation of a charged amino acid into the membrane-spanning domain blocks cell surface transport but not membrane anchoring of a viral glycoprotein.
• Temperature-Sensitive Behavior of the Hemagglutinin in a Temperature-Sensitive Mutant Virion of Sindbis 1