Heteroduplex analysis of the Xenopus RNA polymerase I terminator.
Recent results showed that the Xenopus ribosomal terminator, a conserved 9-bp element ("T2/T3 box"), is a pause signal for the RNA polymerase I-elongation complex (Labhart, P. [1995] Nucleic Acids Res. 23, 2252-2258). Since the terminator is known to function only in one orientation, it was of interest to investigate whether the 9-bp pause element had to be present in both DNA-strands to mediate termination of RNA polymerase I-transcription. The present heteroduplex analysis of the terminator shows that only the double-stranded 9-bp element constitutes a functional terminator. Any single-stranded mutation had the same down-effect as the corresponding double-stranded (homoduplex) mutation. Models for termination by Xenopus RNA polymerase I that are supported or eliminated by the present results are discussed.
Labhart
P
P
Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, CA 92037, USA.
D000818:Animals; D001483:Base Sequence; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D009692:Nucleic Acid Heteroduplexes / Q000235:genetics*; D012318:RNA Polymerase I / Q000235:genetics*; D013728:Terminator Regions, Genetic; D014158:Transcription, Genetic; D014982:Xenopus laevis
D009692:Nucleic Acid Heteroduplexes; D012318:RNA Polymerase I