Cell development discovery changes our understanding of how genes shape early embryos

To fit inside each nucleus, DNA coils around specialized proteins. These spools of wrapped DNA inhibit gene regulatory proteins from binding to protein-coding stretches along the genome, which help keep genes in the “off” position when they’re not needed.

side-by-side comparison of two nuclei with different compaction
Blotchy black regions of a nucleus (left), with normal chromatin compaction (denoted by black spots). Nucleus deficient in the enzymes (right). (Photo credit: Dario Nicetto)

Until now, it was unclear how this DNA packing affected development in early embryos. In a paper published in Science, researchers from the Perelman School of Medicine found that compacted regions along the genome increase at protein-coding genes. Days later in the cell differentiation phase, these domains open to allow certain genes to be read and made into their corresponding proteins.

“This is a fundamental change in our understanding of how genes are controlled in the early embryo,” says Ken Zaret, director of the Institute for Regenerative Medicine and a professor of cell and developmental biology, “even if we can't yet see all the potential clinical impacts.”

First author Dario Nicetto, a postdoctoral fellow at the Institute for Regenerative Medicine’s Zaret Lab, explains that he and coauthors think that during the earliest stages of development, more compacted gene-coding regions arise so that a cell can make rapid “decisions” about which genes should be made into proteins.

Read more at Penn Medicine News.