ABOVE: A retina affected by age-related macular degeneration
JAYAKRISHNA AMBATI, UNIVERSITY OF VIRGINIA
In 2011, ophthalmologist Jayakrishna Ambati of the University of Virginia and his colleagues made a curious observation: In the pigmented retinal layers of human eye samples afflicted with an advanced form of age-related macular degeneration (AMD), they discovered high concentrations of Alu transcripts. Alu is a class of transposable elements, DNA bits that jump around the genome through a copy-paste mechanism that occurs in the nucleus. Further studies by the team suggested that the Alu RNA was somehow causing inflammation and cell death, but it was a mystery how.
Earlier this year, Ambati’s team uncovered an important clue. Surprisingly, in cultured human retinal pigmented epithelium cells, they found that DNA copies of Alu can occur in the cell cytoplasm—in the form of complementary DNA (cDNA) made from messenger RNA. In fact, that was the first evidence that human ...
