trans activation of human immunodeficiency virus type 1 is sequence specific for both the single-stranded bulge and loop of the trans-acting-responsive hairpin: a quantitative analysis.
We have used site-directed mutagenesis to delineate sequence specific domains within the human immunodeficiency virus type 1 (HIV-1) trans-acting-responsive (TAR) RNA element that are required for trans activation by the viral Tat protein. Our data in part corroborate a recent report [S. Feng and E. C. Holland, Nature (London) 334:165-167, 1988] that five nucleotides within the loop (+29 to +33) of the TAR hairpin are important for trans activation. We, however, found no absolute requirement for the CUGGG loop sequence. Mutants with substitutions within the loop retained between 9 and 50% activity compared with the wild type. A second sequence, important for trans activation, was found in the 3-base bulge loop (+22 to +24) of the TAR hairpin. Cross-trans-activation studies of mutant HIV-1 TAR elements with the HIV-2 Tat protein suggest that a similar recognition event(s) forms the basis for trans activation of HIV-1 and HIV-2.
Berkhout
B
B
Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892.
Jeang
K T
KT
D001483:Base Sequence; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics / Q000254:growth & development*; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D012313:RNA / Q000235:genetics*; D015533:Transcriptional Activation; D014775:Virus Activation
D012313:RNA