Every cell in your body has a copy of your genome, tightly coiled and packed into its nucleus. Since every copy is effectively identical, the difference between cell types and their biological functions comes down to which, how and when the individual genes in the genome are expressed, or translated into proteins.
Jennifer Phillips-Cremins, assistant professor in Penn Engineering’s Department of Bioengineering, is a pioneer in this field, known as “3-D Epigenetics.” She and her colleagues have now demonstrated a new technique for quickly creating specific folding patterns on demand, using light as a trigger.
The technique, known as LADL or light-activated dynamic looping, combines aspects of two other powerful biotechnological tools: CRISPR/Cas9 and optogenetics. By using the former to target the ends of a specific genome fold, or loop, and then using the latter to snap the ends together like a magnet, the researchers can temporarily create loops between exact genomic segments in a matter of hours.