New Genetic Editing Enzyme System Developed for Cellular Event Recording

Introduction to CAMERA Technology

Researchers from Harvard University in Cambridge, Massachusetts, have created an innovative molecular biology tool known as CAMERA. This system is designed to document the reactions of bacterial and mammalian cells to various environmental stimuli, utilizing the well-known CRISPR-Cas9 DNA editing technology.

Understanding CRISPR-Cas9

CRISPR-Cas9 is commonly referred to as a set of molecular scissors, allowing scientists to cut specific regions of double-stranded DNA. The process involves incorporating a “guide RNA,” a short sequence of nucleic acids that directs the CRISPR-Cas9 complex to a designated DNA sequence for cutting, facilitated by the Cas9 enzyme.

Mechanism of CAMERA

The CAMERA system works by introducing a pair of short circular DNA fragments containing marker genes with distinct DNA sequences into the cells. These fragments remain inert unless they code for a functional gene. Researchers then employ a modified version of the CRISPR-Cas9 tool, which can be activated by particular stimuli, such as a flashing light at a specific wavelength, a chemical added to the culture medium, or even a gene product from the host cell.

When the specified stimulus is applied, CRISPR-Cas9 is activated and excises a segment from one of the plasmids. The cells can subsequently be collected and processed to extract the circular DNA fragments. By measuring the relative amounts of the two different plasmid types, researchers can indirectly assess how many cells responded to the stimulus and the intensity of that stimulus.

Applications of CAMERA in Research

By merging the precise cutting capabilities of CRISPR-Cas9 with antibiotic resistance genes and two types of circular DNA plasmids, researchers have successfully investigated how long bacterial cells were subjected to antibiotics. This was achieved by analyzing changes in the ratios of the plasmids within the CAMERA-equipped cells after exposure to the antibiotic. Additionally, various CAMERA systems have been developed to respond to specific cellular signals and environmental factors, including nutrients, viruses, and light.

Key Features and Future Potential

Two significant advantages of the CAMERA system are that it requires only 10-100 cells to yield reliable data, and it allows for the recording, erasing, and re-recording of multiple cellular events. This functionality positions CAMERA systems as effective “cell data recorders,” akin to flight data recorders in aviation.

The implications of this technology are vast, providing researchers with valuable insights into numerous biological processes, including aging, cancer development, and embryonic growth. The scientific community is eager to explore the future applications of the CAMERA system.

References

Written by Cindi A. Hoover, Ph.D.
Tang, D.R. Liu, Science. 10.1126/science.aap8992 (2018).
http://science.sciencemag.org/content/359/6377/728.full.