Potent inhibition of HIV-1 replication by a Tat mutant.
Herein we describe a mutant of the two-exon HIV-1 Tat protein, termed Nullbasic, that potently inhibits multiple steps of the HIV-1 replication cycle. Nullbasic was created by replacing the entire arginine-rich basic domain of wild type Tat with glycine/alanine residues. Like similarly mutated one-exon Tat mutants, Nullbasic exhibited transdominant negative effects on Tat-dependent transactivation. However, unlike previously reported mutants, we discovered that Nullbasic also strongly suppressed the expression of unspliced and singly-spliced viral mRNA, an activity likely caused by redistribution and thus functional inhibition of HIV-1 Rev. Furthermore, HIV-1 virion particles produced by cells expressing Nullbasic had severely reduced infectivity, a defect attributable to a reduced ability of the virions to undergo reverse transcription. Combination of these inhibitory effects on transactivation, Rev-dependent mRNA transport and reverse transcription meant that permissive cells constitutively expressing Nullbasic were highly resistant to a spreading infection by HIV-1. Nullbasic and its activities thus provide potential insights into the development of potent antiviral therapeutics that target multiple stages of HIV-1 infection.
Meredith
Luke W
LW
Division of Infectious Diseases, Queensland Institute of Medical Research, Herston, Queensland, Australia.
Sivakumaran
Haran
H
Major
Lee
L
Suhrbier
Andreas
A
Harrich
David
D
D005091:Exons; D019084:Fluorescent Antibody Technique, Indirect; D015696:Gene Products, tat / Q000235:genetics*; D005799:Genes, Dominant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D015497:HIV-1 / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D009154:Mutation; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism; D014158:Transcription, Genetic; D014771:Virion; D014779:Virus Replication / Q000235:genetics*
D015696:Gene Products, tat; D012333:RNA, Messenger; D012367:RNA, Viral; D049452:Green Fluorescent Proteins