Real-time optogenetic control of intracellular protein concentration in microbial cell cultures.
Perturbations in the concentration of a specific protein are often used to study and control biological networks. The ability to "dial-in" and programmatically control the concentration of a desired protein in cultures of cells would be transformative for applications in research and biotechnology. We developed a culturing apparatus and feedback control scheme which, in combination with an optogenetic system, allows us to generate defined perturbations in the intracellular concentration of a specific protein in microbial cell culture. As light can be easily added and removed, we can control protein concentration in culture more dynamically than would be possible with long-lived chemical inducers. Control of protein concentration is achieved by sampling individual cells from the culture apparatus, imaging and quantifying protein concentration, and adjusting the inducing light appropriately. The culturing apparatus can be operated as a chemostat, allowing us to precisely control microbial growth and providing cell material for downstream assays. We illustrate the potential for this technology by generating fixed and time-varying concentrations of a specific protein in continuous steady-state cultures of the model organism Saccharomyces cerevisiae. We anticipate that this technology will allow for quantitative studies of biological networks as well as external tuning of synthetic gene circuits and bioprocesses.
Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA. mmcclean@princeton.edu.
Justin
J
Melendez
Michael
M
Patel
Benjamin L
BL
Oakes
Ping
P
Xu
Patrick
P
Morton
Megan N
MN
McClean
D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D003199:Computer Systems; D056931:Cryptochromes / Q000235:genetics / Q000378:metabolism; D025461:Feedback, Physiological; D042541:Intracellular Space / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D008828:Microbiological Techniques / Q000379:methods; D046210:Microfluidic Analytical Techniques; D008856:Microscopy, Fluorescence; D062308:Optogenetics / Q000379:methods*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism* / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*
D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D056931:Cryptochromes; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C533832:CIB1 protein, Arabidopsis; C103618:CRY2 protein, Arabidopsis