Published On: Thu, Feb 11th, 2016

New imaging technique shows how DNA is stable during chromosomes’ ends

A new imaging technique has authorised researchers during North Carolina State University, a University of North Carolina during Chapel Hill, and a University of Pittsburgh to see how DNA loops around a protein that aids in a arrangement of a special structure in telomeres. The work provides new insights into a structure of telomeres and how they are maintained.

Telomeres are radically caps on a ends of linear chromosomes, that are a structures inside a cells that enclose DNA with a genetic information. In terms of function, telomeres are like a cosmetic cloaking (aglet) on a ends of shoelaces that prevents a laces from unraveling. In healthy cells, telomeres strengthen a chromosome by tucking divided any suspended ends of DNA strands to form a lasso-like structure famous as a T-loop. Without telomeres, a cell’s DNA correct proteins would review a suspended ends as a mangle to be mended and try to possibly connect chromosomes together or send special proteins to digest them away.

Researchers know that a protein called telomeric repeat-binding cause 2 (TRF2) is pivotal to telomeric constructional firmness due to a purpose it plays in combining a T-loop. But researchers didn’t know a mechanics behind a DNA compaction and T-loop arrangement by TRF2.

“TRF2 can compress DNA, that is critical for T-loop formation,” says NC State physicist Hong Wang, lead author of a paper describing a research. “But before to this work, researchers did not know where a DNA was going or how TRF2 compressed it — we could usually see a DNA strand going into and out of TRF2 complexes, though couldn’t see a DNA in a complexes. This is since we were regulating normal atomic force microscopy (AFM) techniques, in that a protein-DNA shows adult as a singular blob, and a DNA trail information is missing.”

The breakthrough came with a new imaging technique, dual-resonance-frequency-enhanced electrostatic force microscopy (DREEM), that was grown by University of North Carolina during Chapel Hill chemist and co-author Dorothy Erie, former UNC and NC State postdoctoral researchers Dong Wu and Parminder Kaur, and was featured progressing this year in Molecular Cell. The technique utilizes a fact that DNA is negatively charged along a backbone. By requesting DC and AC biases between a AFM examine and representation surface, DREEM can detect really diseased electrostatic communication differences when it scans over protein contra DNA regions. In this way, DREEM enables approach cognisance of DNA jacket outward histone proteins.

“DREEM authorised us to see a DNA’s trail by a TRF2 complex,” says Wang. “Based on a DREEM images that we got, we now consider there might be dual orders of DNA compaction within a telomere – first, DNA wraps around a TRF2 protein in a interior of a complex. Then, mixed TRF2 molecules come together and emanate DNA loops that hang out from a TRF2 proteins.

“We consider that this extending loop provides a entering site for a telomere overhangs to tuck in to form a T-loop structure. This routine eventually helps to say a protecting structure that prevents alloy of chromosomes or a delayed erosion of telomere DNA. Our destiny work will try to establish if this is indeed a case.”

The researchers’ work appears in Nature Scientific Reports. The work was upheld by grants from a National Institutes of Health and a commander extend from CHHE during NC State. NC State physicist Robert Riehn, postdoc Jiangguo Lin, connoisseur tyro Preston Countryman and a Opresko lab during a University of Pittsburgh also contributed to a work.

Source: North Carolina State University

About the Author

Leave a comment

XHTML: You can use these html tags: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>