Bacterial repression loops require enhanced DNA flexibility

Nicole A. Becker, Jason D. Kahn, L James Maher III

Research output: Contribution to journalArticle

87 Citations (Scopus)

Abstract

The Escherichia coli lac operon provides a classic paradigm for understanding regulation of gene transcription. It is now appreciated that lac promoter repression involves cooperative binding of the bidentate lac repressor tetramer to pairs of lac operators via DNA looping. We have adapted components of this system to create an artificial assay of DNA flexibility in E. coli. This approach allows for systematic study of endogenous and exogenous proteins as architectural factors that enhance apparent DNA flexibility in vivo. We show that inducer binding does not completely remove repression loops but it does alter their geometries. Deletion of the E. coli HU protein drastically destabilizes small repression loops, an effect that can be partially overcome by expression of a heterologous mammalian HMG protein. These results emphasize that the inherent torsional inflexibility of DNA restrains looping and must be modulated in vivo.

Original languageEnglish (US)
Pages (from-to)716-730
Number of pages15
JournalJournal of Molecular Biology
Volume349
Issue number4
DOIs
StatePublished - Jun 17 2005

Fingerprint

DNA
Lac Repressors
High Mobility Group Proteins
Escherichia coli
Lac Operon
Genes
Proteins
E coli hns protein

Keywords

  • DNA looping
  • HMG
  • HU
  • Lac operon
  • Lac repressor

ASJC Scopus subject areas

  • Virology

Cite this

Bacterial repression loops require enhanced DNA flexibility. / Becker, Nicole A.; Kahn, Jason D.; Maher III, L James.

In: Journal of Molecular Biology, Vol. 349, No. 4, 17.06.2005, p. 716-730.

Research output: Contribution to journalArticle

Becker, Nicole A. ; Kahn, Jason D. ; Maher III, L James. / Bacterial repression loops require enhanced DNA flexibility. In: Journal of Molecular Biology. 2005 ; Vol. 349, No. 4. pp. 716-730.
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