HOME >> BIOLOGY >> NEWS
Optical tweezers show how DNA uncoils

ITHACA, N.Y. -- By using optical tweezers to pull individual strands of chromatin -- the DNA-protein complex that chromosomes are made of -- researchers have seen for the first time how information in fundamental genetic packaging units, called nucleosomes, might become accessible to molecules that "read" it.

The report by physicists and biologists at Cornell University and the University of Massachusetts appears in the current Proceedings of the National Academy of Sciences (Vol. 99, Issue 4), "Mechanical Disruption of Individual Nucleosomes Reveals a Reversible Multistage Release of DNA." It marks the first direct observation of the dynamic structure of individual nucleosomes. Chromosomal DNA is packaged into the compact structure of the nuclesome with the help of specialized proteins called histones. The complex of DNA plus histones in cells of higher organisms is called chromatin.

Michelle D. Wang, assistant professor of physics at Cornell,
who led the scientific team, said
the researchers are proposing a three-stage model for the way in which nucleosomal units in chromatin open to reveal their DNA to enzymes like RNA polymerase.

The three stages became apparent when a nucleosome was uncoiled as the DNA was stretched with increasing force, says Brent Brower-Toland, lead author of the article and a research associate in Cornell's Laboratory of Atomic and Solid State Physics. Describing the release of DNA from a single nucleosome, he says: "When we pulled on an individual chromatin fiber with increasing force, low force initially released 76 base pairs of DNA per nucleosome, then higher forces yielded 80 more base pairs with the histones still bound to the DNA, followed by histone detachment at still higher forces. But, if we released the fiber before the histones were detached, the nucleosomes were able to reassemble themselves and the whole process could be repeated." "Of course the basic plan -- nucleosomes and
'"/>

Contact: Roger Segelken
hrs2@cornell.edu
607-255-9736
Cornell University News Service
4-Mar-2002


Page: 1 2 3

Related biology news :

1. Optically recording millisecond brain nerve impulses
2. Optical trap provides new insights into motor molecules - nature`s ultimate nanomachines
3. Optical microsystems emerge in industrial applications
4. Growing Up On Their Own: Smart Plastics Organize Themselves Into Useful Optical Devices
5. Optical Microscopy Shines Light On Biology
6. Controlling biomolecules with magnetic tweezers
7. With optical tweezers, researchers pinpoint the rhythmic rigidity of cell skeletons

Post Your Comments:
*Name:
*Comment:
*Email:
TAG: Optical tweezers show how DNA uncoils

(Date:7/24/2014)... experts gathered at NJIT this week for an all-day ... U.S. Environmental Protection Agency (EPA) to dredge toxic sediment ... , The EPA has called the plan, which proposes ... capping sections of the riverbed, one of the largest ... be dredged and disposed off-site. , "We need to ...
(Date:7/24/2014)... into the potato genes that best adapt to the ... rainfall and increased extremes of hot and cold temperatures.The ... order to create new potato varieties that will adapt ... to find out how the current potato varieties will ... and lower temperatures. , This research is part of ...
(Date:7/24/2014)... on his work with a new drug that successfully treated ... Houston has received a $250,000 grant to expand his research ... to treat a wider range of autoimmune diseases., Chandra Mohan, ... Engineering at UH, previously published a study in Arthritis Research ... successfully treated lupus in mice and reduced the number of ...
Breaking Biology News(10 mins):Experts Weigh the Pros and Cons of a $1.7 Billion EPA Cleanup Plan for the Passaic River at an NJIT 2Neiker-Tecnalia is researching the potato genes that best adapt to climate change 2Biomedical engineer looks at new applications for novel lupus drug 2Biomedical engineer looks at new applications for novel lupus drug 3
(Date:7/24/2014)... Research and Markets has announced ... 2014-2018" report to their offering.  ... the in vitro growth of plant or animal cells ... biopharmaceutical production. Cell culture is a crucial step in ... cell culture consumables are necessary for the in vitro ...
(Date:7/24/2014)... 2014 SRI International has been awarded a ... of Allergy and Infectious Diseases (NIAID), part of the ... potential therapies for HIV infection and AIDS. The contract ... AIDS and the complications and opportunistic infections associated with ... transmission of HIV. According to the ...
(Date:7/24/2014)... Texas (PRWEB) July 24, 2014 ... Potassium Sulphate Industry” is a professional and in-depth ... report introduces Potassium Sulphate basic information, including ... and industry overview. This research covers the international ... as global industry analysis covering macroeconomic environment & ...
(Date:7/24/2014)... (PRWEB) July 24, 2014 1000 balances ... takes input on customers’ weighing needs and expertly narrows ... shortlist of balances, scales or even terminals. , ... and smallest weight (or select readability instead) and define ... few additional selection criteria narrows down the list to ...
Breaking Biology Technology:Global Cell Culture Market 2014-2018: Key Vendors are Becton, Dickinson and Co, EMD, GE Healthcare, Lonza Group, Sigma Aldrich and Thermo Fisher Scientific 2National Institute of Allergy and Infectious Diseases Awards SRI International Contract to Study New Therapies for HIV and AIDS 2National Institute of Allergy and Infectious Diseases Awards SRI International Contract to Study New Therapies for HIV and AIDS 3Potassium Sulphate Market & SHMP Industry 2014 (Global, China) Analysis Now Available at DeepResearchReports.com 2Potassium Sulphate Market & SHMP Industry 2014 (Global, China) Analysis Now Available at DeepResearchReports.com 3Potassium Sulphate Market & SHMP Industry 2014 (Global, China) Analysis Now Available at DeepResearchReports.com 4
Cached News: