title: HIV-1 TAR as anchoring site for optimized catalytic RNAs.
abstract: Ribozymes have a great potential for developing specific gene silencing molecules. One of the main limitations to ensure the efficient application of ribozymes is to achieve effective binding to the target. Stem-loop domains support efficient formation of the kissing complex between natural antisense molecules and their target sequence. We have characterized catalytic antisense RNA hybrid molecules composed of a hammerhead ribozyme and a stem-loop antisense domain. A series of artificial RNA substrates containing the TAR-RNA stem-loop and a target for the hammerhead ribozyme were constructed and challenged with a catalytic antisense RNA carrying the TAR complementary stem-loop. The catalytic antisense RNA cleaves each of these substrates significantly more efficiently than the parental hammerhead ribozyme. Deletion of the TAR domain in the substrate abolishes the positive effect. These results suggest that the enhancement is due to the interaction of both complementary stem-loop motifs. A similar improvement was corroborated when targeting the LTR region of HIV-1 with either hammerhead- and hairpin-based catalytic antisense RNAs. Our results indicate that the TAR domain can be used as an anchoring site to facilitate the access of ribozymes to their specific target sequences within TAR-containing RNAs. Finally, we propose the addition of stable stem-loop motifs to the ribozyme domain as a rational way for constructing catalytic antisense RNAs.
authors.affiliation: Instituto de Parasitologia y Biomedicina 'López-Neyra', CSIC, Ventanilla 11, E-18001 Granada, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Puerta-Fernandez
authors.forename: Alicia
authors.initials: A
authors.lastname: Barroso-del Jesus
authors.forename: Cristina
authors.initials: C
authors.lastname: Romero-López
authors.forename: Alfredo
authors.initials: A
authors.lastname: Berzal-Herranz
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D020134:Catalytic Domain; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D016325:HIV Long Terminal Repeat / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics*; D009690:Nucleic Acid Conformation; D016372:RNA, Antisense / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016337:RNA, Catalytic / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion; D013379:Substrate Specificity
chemical_list: D016372:RNA, Antisense; D016337:RNA, Catalytic