Related Experiment Video
Updated: Nov 27, 2025

Reliably Engineering and Controlling Stable Optogenetic Gene Circuits in Mammalian Cells
Published on: July 6, 2021
A Logic NAND Gate for Controlling Gene Expression in a Circadian Rhythm in Cyanobacteria
Mieun Lee1, Han Min Woo1,2
1Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea.
Abstract:
To enable circadian control of gene expression in cyanobacteria, we constructed a genetic logic gate (NAND) using orthogonal promoters via modular CRISPR interference. The NAND gates were tested in Synechococcus elongatus PCC 7942 using a fluorescent reporter. The NAND gate dynamics were characterized based on the affinity of the dCas9 complex to the output element. Upon connecting tight gene repressions with the circadian promoter (the purF gene; peak expression at dawn), inversed peak expressions were obtained as an output of the NAND gate although the retroactivities were shown in the ON and OFF states. A dark-responsive genetic element of the NAND gate was also expanded to an AND gate in S. elongatus PCC 7942. These cyanobacterial NAND and AND gates could facilitate the control of gene expressions in dynamic metabolic engineering technologies, thereby enabling the cyanobacteria to serve as biosolar cell factories.
Related Concept Videos
Circadian Rhythms and Gene Regulation
Prokaryotic Transcriptional Activators and Repressors
Transcription of prokaryotic...
Gene Regulation During Sporulation
Biological Clocks and Seasonal Responses
Gene Regulation in Microbial Communities: Quorum Sensing
Global Regulatory Systems

