title: Long-range interactions between transcription factors.
abstract: We discuss a method for analysing the number of GFP-LacI fusion transcription factors bound to a construct of 256 contiguous LacI binding sites using photon bleaching statics. We show by using a combination of imaging of the construct in nanochannels, photon statistics and addition of IGFP that the binding coefficient of the LacI decreases with increasing occupation of the construct, with a binding coefficient of 10(-6) M when only 15 of the 256 possible sites are occupied. We model this effect by assuming that the GFP-LacI dimer introduces elastic strain into the helix by generalized deformations, and that this strain propagates over distances at least as large as the persistence length.
authors.affiliation: Department of Physics, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Yan Mei
authors.initials: YM
authors.lastname: Wang
authors.forename: Jonas O
authors.initials: JO
authors.lastname: Tegenfeldt
authors.forename: Jim
authors.initials: J
authors.lastname: Sturm
authors.forename: Robert H
authors.initials: RH
authors.lastname: Austin