Functional substitution of the basic domain of the HIV-1 trans-activator, Tat, with the basic domain of the functionally heterologous Rev.
The tat gene of HIV is a strong activator of the viral LTR. The Tat protein contains a highly basic domain that is important for its transport to the nuclear/nucleolar locations. The Tat basic domain when fused to Escherichia coli beta-galactosidase directed the chimeric protein to the nucleus and nucleolus. Tat mutants lacking the entire basic domain were severely defective in trans-activation. Substitution of the basic domain of Tat with that of the functionally unrelated HIV-1 Rev protein targeted the chimeric protein to the nucleolus and restored the function of Tat. In contrast, substitution with the nuclear targeting signal (NLS) of SV40 T antigen targeted the chimeric protein to the nucleus and accumulation in the nucleolar region was excluded. The Tat-NLS chimeric protein did not restore the trans-activation function of Tat efficiently. These results indicate that the arginine-rich basic domain of the trans-activator, Tat, and post-transcriptional trans-regulator, Rev, are functionally similar with regard to trans-activation of HIV-1 LTR.
Institute for Molecular Virology, St. Louis University School of Medicine, Missouri 63110.
T
T
Subramanian
M
M
Kuppuswamy
L
L
Venkatesh
A
A
Srinivasan
G
G
Chinnadurai
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D003001:Cloning, Molecular; D015694:Gene Products, rev / Q000235:genetics*; D005814:Genes, Viral; D015756:Genes, tat; D015497:HIV-1 / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D009697:Nucleolus Organizer Region / Q000378:metabolism*; D012045:Regulatory Sequences, Nucleic Acid; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics*; D015533:Transcriptional Activation; D054321:rev Gene Products, Human Immunodeficiency Virus
D015694:Gene Products, rev; D015534:Trans-Activators; D054321:rev Gene Products, Human Immunodeficiency Virus