title: Fusion with an RNA binding domain to confer target RNA specificity to an RNase: design and engineering of Tat-RNase H that specifically recognizes and cleaves HIV-1 RNA in vitro.
abstract: A target RNA/DNA-specific nuclease could be constructed if a specific RNA/DNA binding domain allowing target RNA/DNA recognition was fused to a (deoxy)ribonucleolytic domain allowing target RNA/ DNA cleavage. The design and construction of such a chimeric enzyme could be of value for both basic research involving structure-function relationships and applied research requiring inactivation of harmful RNA/DNA molecules of cellular or pathogenic origin. The feasibility of this designer nuclease approach for inactivating specific RNA/DNA molecules was assessed using human immunodeficiency virus type-1 (HIV-1) RNA as a model. Trans-activator of transcription (Tat) protein is one of the key regulatory proteins encoded by HIV-1. It binds to the trans-activation-responsive (TAR) RNA element located within the 5' non-coding region of HIV-1 RNAs. The TAR RNA binding domain of this protein was fused to the ribonuclease (RNase) H domain of HIV-1 reverse transcriptase (RT). RNase H by itself lacks an RNA binding domain. The chimeric Tat-RNase H protein was shown to specifically recognize and cleave HIV-1 TAR RNA in vitro. Cleavage was abolished by mutations in the Tat binding region within the TAR RNA, indicating that it is specific to HIV-1 TAR RNA.
authors.affiliation: Department of Microbiology, Faculty of Medicine, University of Toronto, Ontario, Canada.
authors.forename: Y F
authors.initials: YF
authors.lastname: Melekhovets
authors.forename: S
authors.initials: S
authors.lastname: Joshi
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D015195:Drug Design; D015696:Gene Products, tat / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics*; D008969:Molecular Sequence Data; D015202:Protein Engineering; D012313:RNA / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry* / Q000378:metabolism; D016914:Ribonuclease H / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D013379:Substrate Specificity; D015533:Transcriptional Activation; D054322:tat Gene Products, Human Immunodeficiency Virus
chemical_list: D015696:Gene Products, tat; D012367:RNA, Viral; D011993:Recombinant Fusion Proteins; D054322:tat Gene Products, Human Immunodeficiency Virus; D012313:RNA; D016914:Ribonuclease H