In Vivo Assembly and Expression of DNA Containing Non-canonical Bases in the Yeast Saccharomyces cerevisiae

Chemically modified nucleic acids are of utmost interest in synthetic biology for creating a regulable and sophisticated synthetic system with tailor-made properties. Implanting chemically modified nucleic acids in microorganisms might serve biotechnological applications, while using them in human cells might lead to new advanced medicines. Previously, we reported that a fully modified DNA sequence (called DZA) composed of the four base-modified nucleotides - 7-deaza-adenine, 5-chlorouracil, 7-deaza-guanine and 5-fluorocytosine - could function as a genetic template in prokaryotic cells, Escherichia coli. Here, we report the synthesis of long, partially, or fully modified DZA fragments that encode the yeast-enhanced red fluorescent protein (yEmRFP). The DZA sequences were directly introduced in the genome of the eukaryotic cells, Saccharomyces cerevisiae, via the yeast natural homologous recombination machinery. The simple and straightforward DZA cloning strategy reported here might be of interest to scientists working in the field of xenobiology in yeast.