Self-catalyzed cyclization of the intervening sequence RNA of Tetrahymena: inhibition by methidiumpropyl.EDTA and localization of the major dye binding sites.
AUTOR(ES)
Tanner, N K
RESUMO
The intervening sequence (IVS) excised from the rRNA precursor of Tetrahymena thermophila is converted to a covalently closed circular RNA in the absence of proteins in vitro. This self-catalyzed cyclization reaction is inhibited by the intercalating dye methidiumpropyl.EDTA (MPE; R.P. Hertzberg and P.B. Dervan (1982) J. Am. Chem. Soc. 104, 313-315). The MPE binding sites have been localized by mapping the sites of MPE.Fe(II) cleavage of the IVS RNA. There are three major binding sites within the 414 nucleotide IVS RNA. Two of these sites coincide with the A.B and 9L.2 pairings. These are structural elements that are conserved in all group I introns and are implicated as being functionally important for splicing. We propose that interaction of MPE with these sites is responsible for dye inhibition of cyclization. The reactions of MPE.Fe(II) with an RNA of known structure, tRNAPhe, and with the IVS RNA were studied as a function of temperature, ionic strength and ethidium concentration. Based on the comparison of the reaction with these two RNAs, we conclude that the dye is a very useful probe for structural regions of large RNAs, while it provides more limited structural information about the small, compact tRNA molecule.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=322085Documentos Relacionados
- Self-catalyzed cyclization of the intervening sequence RNA of Tetrahymena: inhibition by intercalating dyes.
- Self-catalyzed destruction of cytochrome P-450: covalent binding of ethynyl sterols to prosthetic heme.
- Cleavage of chromatin with methidiumpropyl-EDTA . iron(II).
- Map of distamycin, netropsin, and actinomycin binding sites on heterogeneous DNA: DNA cleavage-inhibition patterns with methidiumpropyl-EDTA.Fe(II).
- Secondary structure of the Tetrahymena ribosomal RNA intervening sequence: structural homology with fungal mitochondrial intervening sequences.