NUS Researchers Achieve Multiplexed Optogenetic Control of Yeast Using Red and Blue Light
核心洞察
NUS researchers developed y-iLight, a red-light-responsive protein that controls gene expression in yeast without requiring additional chemical cofactors.
The team overcame cross-sensitivity to blue light by engineering protein modules that suppress unwanted activation, enabling reliable multiplexed control.
Combining red and blue light systems allowed sequential control of compound production and cell separation, demonstrated with the antioxidant luteolin.
Researchers at the National University of Singapore (NUS) have engineered a yeast strain that can be precisely controlled using different colours of light, marking a significant advance in synthetic biology and biomanufacturing. The work, published in May in Nature Communications, demonstrates for the first time a reliable multiplexed optogenetic system in yeast that uses both red and blue light to orchestrate complex, multi-step biological processes.
"By using different colours of light to dictate complex, multi-step processes, we are paving the way to make biological manufacturing more predictable and programmable," said Poh Chueh Loo, associate professor at NUS Synthetic Biology for Clinical and Technological Innovation, who led the research.
Overcoming the Red Light Barrier in Yeast
Optogenetics — the use of light to control cellular activity — has been applied in bacteria and mammalian cells, but adapting it reliably to yeast presented persistent challenges. Red light is particularly desirable because it penetrates deep into biological tissues without causing significant cellular damage. However, existing red light-responsive systems in yeast required multiple introduced genes, additional cofactors, or careful handling to avoid unintended activation, making them difficult to combine with other light-controlled systems.
To address this, the NUS team adapted iLight, a light-sensitive genetic tool previously used in bacteria and mammalian cells, to create a yeast-compatible protein dubbed y-iLight. When exposed to red light, y-iLight binds to specific DNA sequences and activates target genes — all without requiring any chemicals beyond those naturally present in yeast.
"This makes it more cost-effective and reliable, as well as more environment-friendly," said Linus Tan, lead author of the study and a PhD student with the NUS College of Design and Engineering.
Engineering Out Blue Light Interference
A critical hurdle emerged during development: the molecule used to detect red light was also sensitive to blue light, threatening the specificity needed for multiplexed control. The researchers solved this by fusing y-iLight to protein modules designed to block its activity specifically under blue light. Through systematic screening of different fusion combinations, they identified variants that preserved robust red light responsiveness while suppressing unwanted blue light activation.
Multiplexed Control in Action
With a reliable red light system in hand, the team combined it with EL222, an established blue light-responsive protein derived from marine bacteria. This dual-colour platform allowed them to deliver distinct biological instructions to yeast simply by changing the colour of light exposure.
In one demonstration, the researchers engineered yeast to produce luteolin — a natural compound found in fruits and vegetables with antioxidant and anti-inflammatory properties — under blue light, and then triggered the cells to clump together and sink under red light by connecting the flocculation gene FLO1 to a red light-activated genetic switch. This sequential control of production and separation points toward cleaner and more programmable biomanufacturing methods.
The team further showcased the system's precision by engineering yeast to produce different coloured compounds in response to red or blue light, spreading the cells on agar and projecting light through masks to grow multi-colour "living images."
Future Directions
The NUS team is now working to boost the strength and sensitivity of the light-sensitive proteins and aims to introduce additional colours of light for even greater control over biological processes. In the longer term, Poh said the team hopes to bring the technology to market, either by spinning off a start-up or partnering with companies interested in licensing the platform.