How context-specific factors control gene activity

Originally published by Ecole Polytechnique Federale de Lausanne on September 9, 2024

Credit: Pixabay/CC0 Public Domain

Every cell in our body contains the same DNA, yet liver cells are different from brain cells, and skin cells differ from muscle cells. What determines these differences? It all comes down to gene regulation; essentially how and when genes are turned on and off to meet the cell's demands. But gene regulation is quite complex, especially because it is itself regulated by other parts of DNA.

There are two important components that control gene regulation: the first are enhancers, which are short bits of DNA that increase the likelihood that a gene will be activated—even if that gene is far away from the enhancer on the genome.

The second are specialized proteins, generally referred to as "transcription factors" (TFs), which bind to enhancers and, put crudely, control gene expression by "flipping" the genes' on/off switches. TFs come in many different varieties, with current studies estimating over 1600 of them in the human genome alone.

Enhancer 'motifs'

Despite the critical role of enhancers and TFs, scientists have struggled to understand the details of how they interact. Traditional approaches focus on what geneticists refer to as DNA "motifs": specific sequences, or patterns, of DNA that can be found across different parts of the genome, like a recognizable musical motif that appears in different parts of a symphony.

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