RNA-Rep · Repeating cycles of chemically-driven RNA replication within model protocells

Repeating cycles of chemically-driven RNA replication within model protocells

Deciphering how nucleic acids replicated in the absence of genetically encoded enzymes is critical to understanding the onset of Darwinian evolution. One unsolved difficulty with non-enzymatic RNA replication is that non-enzymatic copying of a template strand results in the formation of an RNA duplex, which must then be denatured in order for subsequent rounds of replication to take place. Although RNA strands can be separated by heating, re-annealing kinetically outcompetes slow non-enzymatic copying, thus inhibiting RNA amplification. The project "RNA-Rep" was designed to develop a primitive cell-based method to favour multiple cycling of non-enzymatic RNA replication by physically separating melted strands of RNA in different compartments, so that re-annealing is not possible. The ultimate goal of RNA-Rep was to enable multiple cycles of non-enzymatic RNA replication by exploiting efficient activating agents and prebiotic compartmentalisation. The strategy was to use protocells as self-boundary systems with thermally-driven permeability, allowing for the reshuffling of activated substrates after each non-enzymatic RNA replication cycle. The specific objectives of RNA-Rep were: 1. to identify the optimal compartmentalisation model compatible with prebiotic activation and thermal fluctuations; 2. to evaluate the effect of compartmentalisation on thermally-driven multiple cycling of non-enzymatic RNA replication; 3. to evaluate the effect of free or membrane-bound RNA molecules in the efficiency of non-enzymatic RNA replication. RNA-Rep was a highly original and multidisciplinary project, which combined the strength of organic and supramolecular chemistry with the power of non-enzymatic RNA biochemistry to yield an innovative project that exploited the ER's expertise in protocellular systems and provided the ER with extensive training in organic synthesis, chemical biology and biophysics. While the development of the challenging concepts upon which RNA-Rep was built took longer than foreseen and experimental work was heavily impacted by the pandemic that affected one year of this fellowship, promising results have been obtained regarding the compatibility of prebiotic activation with protocells and the effect of multiple thermal cycling on compartments.

Data: CORDIS, © European Union