A Role of RNA Helicase A in cis-Acting Transactivation Response Element-mediated Transcriptional Regulation of Human Immunodeficiency Virus Type 1.
RNA helicase A (RHA) has two double-stranded (ds) RNA-binding domains (dsRBD1 and dsRBD2). These domains are conserved with the cis-acting transactivation response element (TAR)-binding protein (TRBP) and dsRNA-activated protein kinase (PKR). TRBP and PKR are involved in the regulation of HIV-1 gene expression through their binding to TAR RNA. This study shows that RHA also plays an important role in TAR-mediated HIV-1 gene expression. Wild-type RHA preferably bound to TAR RNA in vitro and in vivo. Overexpression of wild type RHA strongly enhanced viral mRNA synthesis and virion production as well as HIV-1 long terminal repeat-directed reporter (luciferase) gene expression. Substitution of lysine for glutamate at residue 236 in dsRBD2 (RHA(K236E)) reduced its affinity for TAR RNA and impaired HIV-1 transcriptional activity. These results indicate that TAR RNA is a preferred target of RHA dsRBDs and that RHA enhances HIV-1 transcription in vivo in part through the TAR-binding of RHA.
Fujii
R
R
Institute of Applied Biochemistry, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8577, Japan.
Okamoto
M
M
Aratani
S
S
Oishi
T
T
Ohshima
T
T
Taira
K
K
Baba
M
M
Fukamizu
A
A
Nakajima
T
T
D000595:Amino Acid Sequence; D001324:Autoantigens / Q000378:metabolism*; D001665:Binding Sites; D053487:DEAD-box RNA Helicases; D015967:Gene Expression Regulation, Viral; D016325:HIV Long Terminal Repeat; D015497:HIV-1 / Q000235:genetics* / Q000254:growth & development; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D011485:Protein Binding; D020365:RNA Helicases / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism; D016601:RNA-Binding Proteins; D020218:Response Elements; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D019892:eIF-2 Kinase; D000099253:Trans-Activation Responsive RNA-Binding Protein
D001324:Autoantigens; D053487:DEAD-box RNA Helicases; D009363:Neoplasm Proteins; D020365:RNA Helicases; D012330:RNA, Double-Stranded; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D019892:eIF-2 Kinase; D000099253:Trans-Activation Responsive RNA-Binding Protein; C098487:DHX9 protein, human