Orthogonal Light-Activated DNA for Patterned Biocomputing within Synthetic Cells.

Cell-free gene expression is a vital research tool to study biological systems in defined minimal environments and has promising applications in biotechnology. Developing methods to control DNA templates for cell-free expression will be important for precise regulation of complex biological pathways and use with synthetic cells, particularly using remote, nondamaging stimuli such as visible light. Here, we have synthesized blue light-activatable DNA parts that tightly regulate cell-free RNA and protein synthesis. We found that this blue light-activated DNA could initiate expression orthogonally to our previously generated ultraviolet (UV) light-activated DNA, which we used to generate a dual-wavelength light-controlled cell-free AND-gate. By encapsulating these orthogonal light-activated DNAs into synthetic cells, we used two overlapping patterns of blue and UV light to provide precise spatiotemporal control over the logic gate. Our blue and UV orthogonal light-activated DNAs will open the door for precise control of cell-free systems in biology and medicine.

Controlling Synthetic Cell-Cell Communication.

Synthetic cells, which mimic cellular function within a minimal compartment, are finding wide application, for instance in studying cellular communication and as delivery devices to living cells. However, to fully realise the potential of synthetic cells, control of their function is vital. An array of tools has already been developed to control the communication of synthetic cells to neighbouring synthetic cells or living cells. These tools use either chemical inputs, such as small molecules, or physical inputs, such as light. Here, we examine these current methods of controlling synthetic cell communication and consider alternative mechanisms for future use.

Controlling gene expression with light: a multidisciplinary endeavour.

The expression of a gene to a protein is one of the most vital biological processes. The use of light to control biology offers unparalleled spatiotemporal resolution from an external, orthogonal signal. A variety of methods have been developed that use light to control the steps of transcription and translation of specific genes into proteins, for cell-free to in vivo biotechnology applications. These methods employ techniques ranging from the modification of small molecules, nucleic acids and proteins with photocages, to the engineering of proteins involved in gene expression using naturally light-sensitive proteins. Although the majority of currently available technologies employ ultraviolet light, there has been a recent increase in the use of functionalities that work at longer wavelengths of light, to minimise cellular damage and increase tissue penetration. Here, we discuss the different chemical and biological methods employed to control gene expression, while also highlighting the central themes and the most exciting applications within this diverse field.