Exchange, catalysis and amplification of encapsulated RNA driven by periodic temperature changes

Abstract

Growth and division of biological cells is based on the complex orchestration of spatiotemporally controlled reactions driven by highly evolved proteins. In contrast, it remains unknown how their primordial predecessors could achieve a stable inheritance of cytosolic components before the advent of translation. An attractive scenario assumes that periodic changes of environmental conditions acted as pacemakers for the proliferation of early protocells. Using catalytic RNA (ribozymes) as models for primitive biocatalytic molecules, we demonstrate that the repeated freezing and thawing of aqueous solutions enables the assembly of active ribozymes from inactive precursors encapsulated in separate lipid vesicle populations. Furthermore, we show that encapsulated ligase ribozymes can overcome freezing-induced content loss and successive dilution by freeze-thaw driven propagation in feedstock vesicles. Thus, cyclic freezing and melting of aqueous solvents – a plausible physicochemical driver likely present on early Earth – provides a simple scenario that uncouples compartment growth and division from nucleic acid self-replication, while maintaining the propagation of these replicators inside new vesicle populations.

Multispecies autocatalytic RNA reaction networks in coacervates

“…Some of the foundational work involves demonstrations of RNA exchange between a coacervate and its environment Jia et al (2014) and the catalytic activity of RNA cleavage and template-based polymerization in coacervates or ATPS (aqueous two-phase systems) Drobot et al (2018); Poudyal et al (2019); Strulson et al (2012). Furthermore, several recent studies report some critical steps towards the construction of an evolvable coacervate-based protocell, e.g ., catalytic assembly of longer RNA in condensates Le Vay et al (2021), RNA reproduction via ligase activity Iglesias-Artola et al (2022); Salditt et al; Salibi et al. However, the (auto-)catalytic assembly of longer (larger) molecules from constituent fragments, the creation of reaction networks and achieving self-reproduction remain explored.…”