Single-Molecule Studies of Repressor-DNA Interactions Show Long-Range Interactions
We have performed single-molecule studies of GFP-LacI repressor proteins bound to bacteriophage λ DNA containing a 256 tandem lac operator insertion confined in nanochannels. An integrated photon molecular counting method was developed to determine the number of proteins bound to DNA. By using this...
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Published in | Proceedings of the National Academy of Sciences - PNAS Vol. 102; no. 28; pp. 9796 - 9801 |
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Main Authors | , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
National Academy of Sciences
12.07.2005
National Acad Sciences |
Subjects | |
Online Access | Get full text |
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Summary: | We have performed single-molecule studies of GFP-LacI repressor proteins bound to bacteriophage λ DNA containing a 256 tandem lac operator insertion confined in nanochannels. An integrated photon molecular counting method was developed to determine the number of proteins bound to DNA. By using this method, we determined the saturated mean occupancy of the 256 tandem lac operators to be 13, which constitutes only 2.5% of the available sites. This low occupancy level suggests that the repressors influence each other even when they are widely separated, at distances on the order of 200 nm, or several DNA persistence lengths. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 To whom correspondence should be addressed. E-mail: rha@suiling.princeton.edu. Abbreviations: IPMC, integrated photon molecular counting; TIRF, total internal reflection fluorescence; POP-6, performance-optimized linear polyacrylamide; TBE, Tris/borate/EDTA. Contributed by Robert H. Austin, April 29, 2005 Author contributions: Y.M.W., J.O.T., W.R., R.R., E.C.C., J.S., and R.H.A. designed research; Y.M.W., W.R., E.C.C., and R.H.A. analyzed data; W.R., R.R., X.-J.G., L.G., I.G., E.C.C., and J.S. contributed new reagents/analytic tools; and Y.M.W., J.O.T., W.R., E.C.C., and R.H.A. wrote the paper. |
ISSN: | 0027-8424 1091-6490 1091-6490 |
DOI: | 10.1073/pnas.0502917102 |