Led by graduate student Shannon Keenan, the team used light to activate chemical signals in developing fruit flies and traced the effects on a protein called Capicua, or Cic. Located in a cell's nucleus, Cic binds to DNA and performs the specialized task of silencing genes. The study, published in Developmental Cell and made available online March 5, reveals the dynamics of gene repression by this protein.
In a complex piece of music, the silences running through the melody contribute as much to the score's effect as the sounded notes. The biological processes that control development rely on highly sophisticated temporal patterns of gene activation and repression to create life's beautiful symphonies. When a pattern is disrupted, it's like a wrong note in the music. In this case, Cic is a repressor protein that silences certain parts of the genome, allowing other genes to express in harmony with one another. Understanding how repressors like Cic work allows researchers to better conduct the orchestra.
"Signals that tell you not to do something are just as important as signals to do something," said Stanislav Shvartsman, Professor of Chemical and Biological Engineering and the Lewis-Sigler Institute for Integrative Genomics and a group leader at the Flatiron Institute at the Simons Foundation. While both Cic and its target genes were established, little was known about the dynamics of gene repression, according to Shvartsman, the study's principal investigator and Keenan's Ph.D. adviser. "Proteins that activate and repress genes can be likened to the gas pedal and brakes on a car," he said. "We know a lot about how the gas pedal works. This is the first time we are seeing the brakes in action."
Read more at Princeton University
Image: A fruit fly embryo dotted with fluorescent lights, indicating DNA transcription in progress at various points along the abdomen. A recent study gave an unprecedented look at how gene repression works, revealing the dynamics of the system that prevents transcription along certain sections of genetic code. Image courtesy of the researchers