BACKGROUND:  Gene regulation and expression systems have been widely used in both academic research and biotech/pharmaceutical industries. An expression system can be used to express regulatory or therapeutic proteins or RNA sequences in specific cell types and tissues, inducing a serial of cellular responses that lead to particular biological and physiological events. Furthermore, it is very desirable to have a system that can be easily turned on/off to meet various research needs. Currently, the most common way to regulate gene expression is to use chemical compounds, drugs, or enzymes, which can be disturbing, even toxic to the cells. On the other hand, there have been two innovative expression systems that use light signals; however, both systems contain factors only found in plants and bacteria. Therefore, the systems are limited in their applications to bacteria, or require the addition of an expensive chromophore to supplement the culture medium.

INNOVATION:  Researchers at UCLA have discovered how a small flowering plant senses light signals, and also the downstream cellular process that leads to floral initiation. With this breakthrough discovery, UCLA researchers have further constructed two light-regulated gene expression systems applicable to both yeast and human cells. Under these systems, the cells are grown to a large quantity in the dark, and then the cells are simply exposed to blue light to set off the expression of a protein that is of interest.

POTENTIAL APPLICATIONS 

• Eukaryotic expression system used in basic research field and pharmaceutical industry.
• Supplement-free and non-disturbing alternatives to most expression systems in the market, which generally require the addition of enzymes or chemicals.

ADVANTAGES

• Light-inducible, fast and simple.
• No medium supplement is needed, therefore non-toxic and non-disturbing to cells.
• Applicable to both yeast and animal cells including human cells.
• Very potent and inexpensive.

DEVELOPMENT-TO-DATE:  The researchers are currently conducting in vitro testing of the expression system in human cells.

Related Papers (Selected)

• Photoexcited CRY2 interacts with CIB1 to regulate transcription and floral initiation in Arabidopsis. Liu H, Yu X, Li K, Klejnot J, Yang H, Lisiero D, Lin C. Science. 2008 Dec 5;322(5907):1535-9. Epub 2008 Nov 6. [more]

Reference: UCLA Case No. 2009-297