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Cell. 1998 May 29;93(5):897-908.

IHF modulation of Tn10 transposition: sensory transduction of supercoiling status via a proposed protein/DNA molecular spring.

Author information

1
Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.

Abstract

Architectural protein IHF modulates Tn10 transposition in vitro. IHF stimulates transposon excision. Also, separately, IHF forces transposon end/target DNA interactions into a constrained pathway, "channeling," that yields only unknotted intratransposon inversion circles. Negative supercoiling influences both effects, differently. We infer that IHF is an architectural catalyst: it promotes initial transpososome assembly and is then ejected from the transpososome. IHF then rebinds, altering transpososome conformation to promote channeling. We also infer that the developing transpososome is a molecular spring: DNA provides basic elasticity; a conformational change in transposase provides force; and IHF and/or supercoiling provide conformational inputs. In vivo, IHF is a sensory transducer of chromosomal supercoiling status: with supercoiling absent, IHF is "supercoiling relief factor"; with supercoiling present, stimulation and channeling comprise a homeostatic pair such that modest changes in chromosome condition strongly influence transpositional outcome.

PMID:
9630232
DOI:
10.1016/s0092-8674(00)81449-x
[Indexed for MEDLINE]
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