from the summary of the paper by Sharon E. Torigoe, Debra L. Urwin, Haruhiko Ishii, Douglas E. Smith, and James T. Kadonaga.
Graphical Abstract
Posted on 08/18/2011 12:14:07 PM PDT by decimon
Basic biology textbooks may need a bit of revising now that biologists at UC San Diego have discovered a never-before-noticed component of our basic genetic material.
According to the textbooks, chromatin, the natural state of DNA in the cell, is made up of nucleosomes. And nucleosomes are the basic repeating unit of chromatin.
When viewed by a high powered microscope, nucleosomes look like beads on a string (photo at right). But in the August 19th issue of the journal Molecular Cell, UC San Diego biologists report their discovery of a novel chromatin particle halfway between DNA and a nucleosome (photo at left). While it looks like a nucleosome, they say, it is in fact a distinct particle of its own.
"This novel particle was found as a precursor to a nucleosome," said James Kadonaga, a professor of biology at UC San Diego who headed the research team and calls the particle a "pre-nucleosome." "These findings suggest that it is necessary to reconsider what chromatin is. The pre-nucleosome is likely to be an important player in how our genetic material is duplicated and used."
The biologists say that while the pre-nucleosome may look something like a nucleosome under the microscope, biochemical tests have shown that it is in reality halfway between DNA and a nucleosome.
These pre-nucleosomes, the researchers say, are converted into nucleosomes by a motor protein that uses the energy molecule ATP (see graphic).
"The discovery of pre-nucleosomes suggests that much of chromatin, which has been generally presumed to consist only of nucleosomes, may be a mixture of nucleosomes and pre-nucleosomes," said Kadonaga. "So, this discovery may be the beginning of a revolution in our understanding of what chromatin is."
"The packaging of DNA with histone proteins to form chromatin helps stabilize chromosomes and plays an important role in regulating gene activities and DNA replication," said Anthony Carter, who oversees chromatin grants at the National Institute of General Medical Sciences of the National Institutes of Health, which funded the research. "The discovery of a novel intermediate DNA-histone complex offers intriguing insights into the nature of chromatin and may help us better understand how it impacts these key cellular processes."
This link has the pictures that are referred to in the article...
http://ucsdnews.ucsd.edu/newsrel/science/2011_08nucleosome.asp
I found some stuff on DNA and ATP dependent nucleosome remodeling, but I don’t understand it. However, I am interested in any discussion about it, and will hang around and try not to be a nuisance.
You’re right, what’s the difference really? I suppose Addams is the better singer but other than that... :)
I've been told my DNA looks like a pearl necklace.
Probably this started with Cro Matin man.
Graphical Abstract
ATP?!? Oh, NO!!!!! Does this mean I have to relearn a REVISED Kreb's Cycle? Noooooooooooooooooo!
Are there no editors or proofreaders for pressors?
Do I have to retake AP Bio?
Yes. And Reuters Bio.
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