Elastin fibers are insoluble even in hot, basic solution, but they are made up of identical, soluble tropoelastin monomers. These monomers are defined by a pentapeptide repetitive motive, Val-Pro-Gly-X-Gly, which is responsible for many of elastin’s properties, in addition to lysine-based cross-linking domains. The intrinsically random and modular structure of tropoelastin makes it suitable for production via circular mRNA. While most mRNA represents the entire sequence of a protein and proceeds linearly from start codon to stop codon, this is not an absolute requirement for translation. Work by the 2014 and 2015 Gifu IGEM teams showed the efficacy of an mRNA circularization device, which could be used to produce translated protein product when a complete coding sequence was enclosed. In addition, they demonstrated that without a stop codon translation would occur for multiple rounds of the same coding sequence with eventual random termination of translation. This process was adapted to produce long tropoelastin-like monomers using a subset of human tropoelastin exons representing alternating cross-linking and coacervation domains, replicating many of the properties which make tropoelastin both interesting and useful.