Wednesday, November 27, 2019

Little DNA SpaghettOs splashing around in your nuclei.

\Linda and her life-long friend Pat

Long, long ago I blogged that it seemed as though biomedical research was a babushka doll; every time you solved a problem another emerged.  Well, it still seems that way; the deeper we probe into how our system works, the more mystifying it appears.  If you don’t believe me, read this:


You already know that our DNA comes in distinct linear segments called chromosomes, and that when a cell divides these chromosomes are duplicated and divvied up evenly.  You also know that our cells have elaborate means of selecting which genes are activated at the correct time and place; we call these controls epigenetic markers.  You may not have known that one of these epigenetic controls involves tightly wrapping the linear chromosomes around little knots of things called histones, thus preventing the messenger RNA strips from translating selected genes into proteins.
 
Well, now it appears that a cell’s entire DNA is not contained in chromosomes; there exist numerous small circles of “extra chromosomal” DNA swimming around in the nuclear cytoplasm.  Moreover, when a cell splits these little circles don’t necessarily divide evenly.  These little circles come in many sizes, and are numerous.    What they do is not at all clear, but you can bet your MAGA cap that they’re doing something; probably several things in fact, and some of them important.  Inevitably, much research is underway.

Babushka  dolls.  Full employment for molecular biologists until the end of time.

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