Sprecher
Beschreibung
Philipp Holliger, PhD,
Program Leader / Head of PNAC division
MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
email: ph1@mrc-lmb.cam.ac.uk
A critical event in the origin of life is thought to have been the emergence of an RNA molecule capable of self-replication as well as mutation, and hence evolution towards ever more efficient replication. Although this ancestral replicase appears to have been lost, key aspects of RNA-catalyzed RNA replication can be studied “by proxy” with the use of modern RNA enzymes (ribozymes) generated by in vitro evolution.
Starting from the original RNA polymerase ribozyme (RPR) [1] we have evolved RPRs that are capable of the templated synthesis of another simple ribozyme [2] or long (> 200 nt), unstructured RNA oligomers [3]. However, none of these RPRs was capable of self-replication.
In this talk I’ll describe the more recent engineering and de novo discovery of RPRs that utilize trinucleotide triphosphates as their main substrates. This unlocks the copying of even highly structured RNA templates and enables non-canonical reverse and primer-free replication modes [4] and - in the case of a recently discovered small RPR - the templated synthesis of its own (+) and (-) strands, an important step towards self-replication [5].
I’ll also be discussing how structured media such as the eutectic phase of water ice - as well as coupled pH / freeze-thaw cycles [6] – can aid RPR function and enable the replication of double-stranded RNAs over many cycles.
[1] Johnston WK, Unrau PJ, Lawrence MS, Glasner ME & Bartel DP (2001) RNA-Catalyzed RNA Polymerization: Accurate and General RNA-Templated Primer Extension. Science 292, 1319-1325.
[2] Wochner A, Attwater J, Coulson A & Holliger P (2011) Ribozyme-catalyzed transcription of an active ribozyme. Science 332, 209-212.
[3] Attwater J, Wochner A & Holliger P (2013) In-ice evolution of RNA polymerase ribozyme activity. Nature Chem 5, 1011-1018.
[4] Attwater J, Raguram A, Morgunov AS, Gianni E & Holliger P (2018) Ribozyme-catalysed RNA synthesis using triplet building blocks. eLife, 7: e35255
[5] Gianni E, Kwok SLY, Wan CJK, Goeij K, Clifton BE, Attwater J & Holliger P (2024) A polymerase ribozyme that can synthesize both itself and its complementary strand. bioRxiv; doi: https://doi.org/10.1101/2024.10.11.617851
[6] Attwater J, Augustin T, Curran JF, Kwok SLY, Gianni E & Holliger P (2025) Trinucleotide substrates under pH–freeze–thaw cycles enable open-ended exponential RNA replication by a polymerase ribozyme. Nature Chem. https://doi.org/10.1038/s41557-025-01830-y
