Triggering genes in a flash

Flicking a switch can now turn on much more than just the lights. Thanks to a technique developed by a team of biologists in California, a light pulse can activate or deactivate selected genes in cells.

Sae Shimizu-Sato of the University of California, Berkeley and the U.S. Department of

Agriculture in Albany, Calif., and her colleagues rendered a yeast gene light-triggerable by splicing plant genes into yeast cells. Those genes included one for a light-sensitive plant protein called a phytochrome, which changes shape upon absorbing certain wavelengths of red light.

In one configuration, the phytochrome joins with other proteins to turn on the selected yeast gene. Switched to another shape by a dose of different red light, the phytochrome releases those partner proteins, shutting off the gene.

The team described its new technique in the October Nature Biotechnology. In a commentary in the same issue, Andrew R. Mendelsohn of the Molecular Sciences Institute in Berkeley, Calif., says the method may give researchers unprecedented control over biological processes such as cell communication and some enzyme functions. If so, Mendelsohn declares, “this report would seem to signal the dawn of the age of light-based biological engineering.”


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