Supercoil-induced extrusion of a regulatory DNA hairpin
AUTOR(ES)
Dai, Xing
FONTE
The National Academy of Sciences of the USA
RESUMO
Bacteriophage N4 virion RNA polymerase (N4 vRNAP) promoters contain inverted repeats, which form a 5- to 7-base-pair stem, 3-base loop hairpin that is required for vRNAP recognition. We show that, contrary to certain theoretical predictions, hairpin extrusion can occur at physiological superhelical densities in a Mg2+-dependent manner. Specific sequences on the template strand are required for hairpin extrusion. These sequences define stable DNA hairpins that are relatively unreactive to single strand-specific probes. In addition, a specific stable hairpin-inducing sequence can regulate transcription in vivo. Thus, a DNA structure, in its natural environment, is involved in transcriptional regulation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=20060Documentos Relacionados
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