Mutational analysis of HIV-1 Nef: identification of two mutants that are temperature-sensitive for CD4 downregulation.
The Nef protein of HIV-1 is capable of performing at least two functions: reduction of cell-surface expression of CD4, the viral receptor, and enhancement of HIV-1 infectivity. Here we report the results of assays of CD4 downregulation by nef point mutants. Areas of high charge density and highly conserved sequence motifs were targeted. In general, mutations in the carboxyl-terminal half of the protein had more deleterious effects than did those in the amino-terminal half. A single mutant nef allele was identified which encoded a stable protein but was completely inactive. Two mutant Nef proteins exhibited temperature-sensitive phenotypes in assays of CD4 downregulation.
Aiken
C
C
Infectious Disease Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA.
Krause
L
L
Chen
Y L
YL
Trono
D
D
D000595:Amino Acid Sequence; D015704:CD4 Antigens / Q000378:metabolism*; D002460:Cell Line; D015536:Down-Regulation; D015693:Gene Products, nef / Q000235:genetics* / Q000378:metabolism; D015497:HIV-1 / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017354:Point Mutation; D013696:Temperature; D054311:nef Gene Products, Human Immunodeficiency Virus
D015704:CD4 Antigens; D015693:Gene Products, nef; D054311:nef Gene Products, Human Immunodeficiency Virus