Bio-Synthesis Newsletter - February 2018

CRISPR for Cancer Immunotherapy

Recently a nanotechnology strategy was developed for the delivery of the CRISPR Cas gene editing system into cells using arginine nanoparticles to generate signal regulatory protein α (SIRP-α) knockout macrophages. The signal guide RNA (sgRNA) and Cas9 protein required for gene editing were co-delivered into the cells to knock out the “don’t eat me signal” in macrophages. The innate phagocytic capabilities of the macrophages are increased by 4-fold when this signal is turned off. This approach makes it possible to create “weaponized” macrophages that can kill cancer cells during immunotherapy.

Heparin binding peptide for microtissue assembly

Specific microtissues are needed to enable tissue repair as they occur in orthopedic injuries. Microtissues containing multiple cell types have been used as models for tissue repair applications. Lei et al. now investigated the binding between the heparin-binding peptide and a heparin-coated cell surfaces for their ability to promote assembly of mesenchymal stem cell (MSC) spheroids. Combining spheroids with both coatings promoted the spheroids to assemble into multi-aggregated structures. This type of self-assembly method is thought to be applicable for a wide range of cell aggregation methods needed for the repair of damaged tissue.

BNA modification for mismatch-repair

Synthetic single-stranded DNA oligonucleotides (ssODNs) allow the generation of subtle genetic modifications in cells. The presence of bridged nucleic acids (BNAs) in ssODNs at mismatching bases or directly adjacent bases allows 1-, 2-, or 3-base pair substitutions in DNA mismatch repair (MMR)-deficient mouse embryonic stem cells. Ravesteyn and coworkers demonstrated that incorporation of BNAs in ssODNs at mismatching bases prevents MMR-mediated suppression of gene modification in mouse embryonic stem cells and E. coli.

A Peptide Tether for RNA

The 22 amino acid RNA-binding domain of the λ bacteriophage antiterminator protein (λN 1-22) or λN peptide allows tagging of proteins to RNAs tagged with the boxB hairpin motif. Because of its small size, the peptide interferes less with the function of tagged proteins. Besides other application λN-tethering includes tethering of eukaryotic translation initiation factors to a reporter mRNA or the hUpf3b protein to the 3’-untranslated region (UTR) of a reporter mRNA. This tethering approach allows studying the nonsense-mediated decay (NMD) of mRNAs.

Please note that creation and use of synthetic oligos for CRISPR applications requires a license from ERS genomics, the holders of IP for CRISPR technology. We do not have a license to provide synthetic oligos used in CRISPR technology from ERSGenomics. Contact ERSGenomics.com for further information.