heterochromatin tagged posts

You may have heard of the fantastic-sounding “dark side of the genome.” This poorly studied fraction of DNA, known as heterochromatin, makes up around half of your genetic material, and scientists are now starting to unravel its role in your cells.

For more than 50 years, scientists have puzzled over the genetic material contained in this “dark DNA.” But there’s a growing body of evidence showing that its proper functioning is critical for maintaining cells in a healthy state. Heterochromatin contains tens of thousands of units of dangerous DNA, known as “transposable elements” (or TEs)...

An artistic rendering of the mechanism responsible for relocalization of heterochromatic repair sites during homologous recombination. A nuclear myosin walks along a dynamic nuclear actin filament, carrying broken DNA for repair. Credit: Yekaterina Kadyshevskaya, USC

‘Walking molecules’ haul away damaged DNA to the cell’s emergency room. Amid the rise of CRISPR and genome editing, scientists are still learning more about DNA repair and its significance in aging and diseases such as cancer. The cell has its own paramedic team and emergency room to aid and repair damaged DNA, a new USC Dornsife study reveals.

The findings are timely, as scientists are delving into the potential of genome editing with the DNA-cutting enzyme, CRISPR-Cas9, to treat diseases or to advance scientific knowledge ab...

Activity with age. Fluorescence in the fat body of fruit flies tracks the activity of transposable elements of DNA. It increases markedly with age. Credit: Jason Wood/Brown University

A new study increases and strengthens the links that have led scientists to propose the “transposon theory of aging.” Transposons are rogue elements of DNA that break free in aging cells and rewrite themselves elsewhere in the genome, potentially creating lifespan-shortening chaos in the genetic makeups of tissues. As cells get older, prior studies have shown, tightly wound heterochromatin wrapping that typically imprisons transposons becomes looser, allowing them to slip out of their positions in chromosomes and move to new ones, disrupting normal cell function...