Welcome to our pick of papers and articles from last month. These are a collection of the synthetic biology papers that have captured our attention and that we think you should know about. Maybe you’ve seen some others you’d like to tell us about. Send us a comment or tweet us at @synbiobydesign. See papers from early December here.
A wealth of synthetic promoters to speed up circuit design
A new library of E. coli promoters with a multitude of dynamic ranges was built by Chen et al. This was achieved using a modular approach that combined different components, including the -35 site and the -10 site, and regions upstream/between these. These fine-tuned promoters were then incorporated into logic gate circuitry to make transcriptional AND gates. An additional feature is the nonleaky nature of the promoters.
Virus stamping – the new method for gene delivery
Virus stamping is the new way of delivering new genes inside particular cells within whole tissues by means of viruses. This is applicable to multiple cell types and viruses. Cell on the surface of tissues can be transformed by a virus on the surface of a glass pipette tip poking the target cells. For cells in tissue, magnetic forces are used to aid delivery of the virus to the desired location.
Not feeling blue in blue jeans
A non-toxic version of indigo – the dye responsible for the classic blue colour of denim – has been synthesised by expressing a relevant glucosyltransferase from the indigo plant in E. coli. This bypasses the standard method of production which requires chemical treatment (including the use of formaldehyde and cyanide) that ends up polluting rivers.
Future developments of DNA
While not a primary research paper, this review by Kohman et al. is a brilliant perspective piece on DNA now, in the future and its development in 4 key areas: DNA as a building material for delivery of compounds, engineering microbial genomes for industrial purposes, advancing knowledge of evolution by synthesising whole genomes and barcoding biological systems for studying many molecules simultaneously in situ.
Potential pitfalls of CRISPR-Cas9?
Additionally, a pre-print published on biorXiv has uncovered some flaws with the use of CRISPR-Cas9 for gene therapy in humans. It appears that immune responses are already in place for the Cas9 proteins, as the majority are derived from the pathogenic Staphylococcus aureus and Streptococcus pyogenes. The potential immunogenicity issues complicate future clinical trials.