Synthetic Genetic Polymers Functioning to Store and Propagate Information by Genetic Alphabet Expansion

Abstract

Expansion of the genetic alphabet by an artificial extra base pair (unnatural base pair) could provide a new biotechnology in a synthetic biology area, enabling the site-specific incorporation of functional components of interest into nucleic acids and proteins. To store and propagate genetic information, unnatural base pairs require high exclusive selectivity as a third base pair in polymerase reactions. Recently, several unnatural base pairs that function in replication, transcription and/or translation have been developed. For replication, unnatural base pairs require highly selective complementarity in their base-pair formation. For transcription, unnatural base pairs with the unidirectional function to incorporate an unnatural base substrate into RNA opposite its pairing partner in templates can be used. For translation, the thermal stability and selectivity of the unnatural base pair formation in the codon–anticodon interaction are important. According to these categories, various unnatural base pairs are described, along with their applications. Keywords: unnatural base pair; genetic alphabet expansion; PCR ; T7 transcription; real-time qPCR ; SELEX (in-vitro selection)