New research shows how genes are turned on and off

Yeast, that simple organism essential to making beer and bread, researchers at Cornell University have uncovered a key mechanism for controlling genes.

Gene transcription — the sophisticated process our cells use to read genetic information stored in DNA — has long been thought to be activated when specific regulatory factors target specific DNA sequences. In new research, a team of Cornell scientists discovered that certain genes have their transcription-regulating factors and cofactors already present but in a latent state. With the appropriate signals, these “balanced” genes become highly active.

Using CRISPR techniques, the researchers removed parts of the yeast transcription machinery to systematically study their role in regulating genes. Yeast and humans share much of the same molecular machinery to regulate their genes, so yeast provides an excellent model for understanding gene regulation in humans.

“It’s like playing Jenga, where you remove a block from a tower of blocks and see if the whole thing collapses. This is how we learn how protein machines work in cells,” said B. Franklin Pugh, professor of molecular biology and genetics and corresponding author of the study.

“The value of readiness is that certain genes, like environmental response genes, can respond quickly to a changing environment, such as when yeast encounters bread sugar and metabolizes it, which causes bread dough to rise,” Pugh said.

“Building on years of existing research and combining it with modern and elegant genomics tools has helped us to fill gaps in current knowledge and make new discoveries,” said Chitvan Mittal, first author and research associate at the Baker Institute for Animal Health in the Faculty of Veterinary Medicine.

The study was published in Genes & Development.