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Related Experiment Videos

DNA supercoiling in vivo.

G N Giaever1, L Snyder, J C Wang

  • 1Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, MA 02138.

Biophysical Chemistry
|February 1, 1988
PubMed
Summary
This summary is machine-generated.

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DNA topoisomerase I mutants in E. coli show increased DNA supercoiling and growth inhibition when the topA gene is switched off. This leads to DNA structural changes, unlike in S. cerevisiae where DNA topology is less affected.

Area of Science:

  • Molecular Biology
  • Genetics
  • Biochemistry

Background:

  • DNA topology is crucial for cellular processes.
  • DNA topoisomerases regulate DNA supercoiling and structure.
  • Understanding DNA topology in different organisms is essential.

Purpose of the Study:

  • To investigate the role of DNA topoisomerase I in maintaining intracellular DNA topology.
  • To compare the effects of topoisomerase I deficiency in Escherichia coli and Saccharomyces cerevisiae.
  • To elucidate the impact of altered DNA supercoiling on DNA structure and cell growth.

Main Methods:

  • Utilizing DNA topoisomerase mutants of E. coli and S. cerevisiae.
  • Analyzing the topological state of intracellular DNA.
  • Observing changes in DNA supercoiling and helical structure (B-DNA to Z-DNA transition).

Related Experiment Videos

  • Monitoring cell growth inhibition.

    • Main Results:

    • In E. coli, switching off the topA gene increased negative supercoiling and inhibited cell growth.
    • A d(pCpG)16.d(pCpG)16 sequence in E. coli shifted from B-DNA to Z-DNA in vivo upon topA gene inactivation.
    • In S. cerevisiae, intracellular DNA topology was minimally affected by cellular topoisomerase levels.

    Conclusions:

    • DNA topoisomerase I plays a critical role in regulating DNA topology and cell viability in E. coli.
    • Altered DNA supercoiling can induce significant structural transitions in DNA, impacting cellular functions.
    • S. cerevisiae exhibits a more robust DNA topological regulation system compared to E. coli.