Supercoiling of the DNA template during transcription

Journal Article · Thu Oct 01 04:00:00 EDT 1987 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.84.20.7024· OSTI ID:6945749

Liu, L F; Wang, J C

Transcription of a right-handed double-helical DNA requires a relative rotation of the RNA polymerase and its nascent RNA around the DNA. The authors describe conditions under which the resistance to the rotational motion of the transcription ensemble around the DNA can be large. In such cases, the advancing polymerase generates positive supercoils in the DNA template ahead of it and negative supercoils behind it. Mutual annihilation of the positively and negatively supercoiled regions may be prevented by anchoring points on the DNA to a large structure, or, in the case of an unanchored plasmid, by the presence of two oppositely oriented transcription units. In prokaryotes, DNA topoisomerase I preferentially removes negative supercoils and DNA gyrase (topoisomerase II) removes positive ones. The model thus provides an explanation for the experimentally observed high degree of negative or positive supercoiling of intracellular pBR322 DNA when DNA topoisomerase I or gyrase is respectively inhibited. They discuss the implications of the module in terms of supercoiling regulation, DNA conformational transitions, and gene regulation in both prokaryotes and eukaryotes.

• Research Organization: Johns Hopkins Univ., Baltimore, MD (USA)
• OSTI ID: 6945749
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States) Vol. 84:20; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
CELL CONSTITUENTS
CONFORMATIONAL CHANGES
DNA
ENZYMES
GENE REGULATION
ISOMERASES
NUCLEIC ACIDS
NUCLEOTIDYLTRANSFERASES
ORGANIC COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
PLASMIDS
POLYMERASES
RNA
RNA POLYMERASES
STEREOCHEMISTRY
TRANSCRIPTION
TRANSFERASES