scholarly journals RNA Back and Forth: Looking through Ribozyme and Viroid Motifs

Viruses ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 283 ◽  
Author(s):  
Marie-Christine Maurel ◽  
Fabrice Leclerc ◽  
Jacques Vergne ◽  
Giuseppe Zaccai

Current cellular facts allow us to follow the link from chemical to biochemical metabolites, from the ancient to the modern world. In this context, the “RNA world” hypothesis proposes that early in the evolution of life, the ribozyme was responsible for the storage and transfer of genetic information and for the catalysis of biochemical reactions. Accordingly, the hammerhead ribozyme (HHR) and the hairpin ribozyme belong to a family of endonucleolytic RNAs performing self-cleavage that might occur during replication. Furthermore, regarding the widespread occurrence of HHRs in several genomes of modern organisms (from mammals to small parasites and elsewhere), these small ribozymes have been regarded as living fossils of a primitive RNA world. They fold into 3D structures that generally require long-range intramolecular interactions to adopt the catalytically active conformation under specific physicochemical conditions. By studying viroids as plausible remains of ancient RNA, we recently demonstrated that they replicate in non-specific hosts, emphasizing their adaptability to different environments, which enhanced their survival probability over the ages. All these results exemplify ubiquitous features of life. Those are the structural and functional versatility of small RNAs, ribozymes, and viroids, as well as their diversity and adaptability to various extreme conditions. All these traits must have originated in early life to generate novel RNA populations.

Author(s):  
Marie-Christine Maurel ◽  
Fabrice Leclerc ◽  
Jacques Vergne ◽  
Giuseppe Zaccai

Current cellular facts allow us to follow the link from chemical to biochemical metabolites, from the ancient to the modern world. In this context, the "RNA world" hypothesis proposes that early in the evolution of life, the ribozyme was responsible for the storage and transfer of genetic information and for the catalysis of biochemical reactions. Accordingly, the hammerhead ribozyme (HHR) and the hairpin ribozyme, belong to a family of endonucleolytic RNAs performing self-cleavage that might occur during replication. Furthermore, regarding the ultraconserved occurrence of HHR in several genomes of modern organisms (from mammals to small parasites and elsewhere), these small ribozymes have been regarded as living fossils of a primitive RNA world. They fold into 3D structures that generally require long-range intramolecular interactions to adopt the catalytically active conformation under specific physicochemical conditions. By studying viroids as plausible remains of ancient RNA, we recently demonstrated that they replicate in non-specific hosts, emphasizing their adaptability to different environments, which enhanced their survival probability over the ages. All these results exemplify ubiquitously features of life. Those are the versatility and efficiency of small RNAs, viroids and ribozymes, as well as their diversity and adaptability to various extreme conditions. All these traits must have originated in early life to generate novel RNA populations.


Author(s):  
Marie-Christine Maurel ◽  
Fabrice Leclerc ◽  
Jacques Vergne ◽  
Giuseppe Zaccai

Current cellular facts allow us to follow the link from chemical to biochemical metabolites, from the ancient to the modern world. In this context, the "RNA world" hypothesis proposes that early in the evolution of life, the ribozyme was responsible for the storage and transfer of genetic information and for the catalysis of biochemical reactions. Accordingly, the hammerhead ribozyme (HHR) and the hairpin ribozyme, belong to a family of endonucleolytic RNAs performing self-cleavage that might occur during replication. Furthermore, regarding the ultraconserved occurrence of HHR in several genomes of modern organisms (from mammals to small parasites and elsewhere), these small ribozymes have been regarded as living fossils of a primitive RNA world. They fold into 3D structures that generally require long-range intramolecular interactions to adopt the catalytically active conformation under specific physicochemical conditions. By studying viroids as plausible remains of ancient RNA, we recently demonstrated that they replicate in non-specific hosts, emphasizing their adaptability to different environments, which enhanced their survival probability over the ages. All these results exemplify ubiquitously features of life. Those are the versatility and efficiency of small RNAs, viroids and ribozymes, as well as their diversity and adaptability to various extreme conditions. All these traits must have originated in early life to generate novel RNA populations.


2019 ◽  
Vol 47 (13) ◽  
pp. 6569-6577 ◽  
Author(s):  
Christine He ◽  
Adriana Lozoya-Colinas ◽  
Isaac Gállego ◽  
Martha A Grover ◽  
Nicholas V Hud

Abstract The RNA World hypothesis posits that RNA was once responsible for genetic information storage and catalysis. However, a prebiotic mechanism has yet to be reported for the replication of duplex RNA that could have operated before the emergence of polymerase ribozymes. Previously, we showed that a viscous solvent enables information transfer from one strand of long RNA duplex templates, overcoming ‘the strand inhibition problem'. Here, we demonstrate that the same approach allows simultaneous information transfer from both strands of long duplex templates. An additional challenge for the RNA World is that structured RNAs (like those with catalytic activity) function poorly as templates in model prebiotic RNA synthesis reactions, raising the question of how a single sequence could serve as both a catalyst and as a replication template. Here, we show that a viscous solvent also facilitates the transition of a newly synthesized hammerhead ribozyme sequence from its inactive, duplex state to its active, folded state. These results demonstrate how fluctuating environmental conditions can allow a ribozyme sequence to alternate between acting as a template for replication and functioning as a catalyst, and illustrate the potential for temporally changing environments to enable molecular processes necessary for the origin of life.


Author(s):  
Steven E. Vigdor

Chapter 7 describes the fundamental role of randomness in quantum mechanics, in generating the first biomolecules, and in biological evolution. Experiments testing the Einstein–Podolsky–Rosen paradox have demonstrated, via Bell’s inequalities, that no local hidden variable theory can provide a viable alternative to quantum mechanics, with its fundamental randomness built in. Randomness presumably plays an equally important role in the chemical assembly of a wide array of polymer molecules to be sampled for their ability to store genetic information and self-replicate, fueling the sort of abiogenesis assumed in the RNA world hypothesis of life’s beginnings. Evidence for random mutations in biological evolution, microevolution of both bacteria and antibodies and macroevolution of the species, is briefly reviewed. The importance of natural selection in guiding the adaptation of species to changing environments is emphasized. A speculative role of cosmological natural selection for black-hole fecundity in the evolution of universes is discussed.


2006 ◽  
Vol 361 (1474) ◽  
pp. 1751-1760 ◽  
Author(s):  
William R Taylor

The RNA world hypothesis requires a ribozyme that was an RNA-directed RNA polymerase (ribopolymerase). If such a replicase makes a reverse complementary copy of any sequence (including itself), in a simple RNA world, there is no mechanism to prevent self-hybridization. It is proposed that this can be avoided through the synthesis of a parallel complementary copy. The logical consequences of this are pursued and developed in a computer simulation, where the behaviour of the parallel copy is compared to the conventional reverse complementary copy. It is found that the parallel copy is more efficient at higher temperatures (up to 90°C). A model for the ribopolymerase, based on the core of the large subunit (LSU) of the ribosome, is described. The geometry of a potential active site for this ribopolymerase suggests that it contained a cavity (now occupied by the aminoacyl-tRNA) and that an amino acid binding in this might have ‘poisoned’ the ribopolymerase by cross-reacting with the nucleoside-triphosphate before polymerization could occur. Based on a similarity to the active site components of the class-I tRNA synthetase enzymes, it is proposed that the amino acid could become attached to the nascent RNA transcript producing a variety of aminoacylated tRNA-like products. Using base-pairing interactions, some of these molecules might cross-link two ribopolymerases, giving rise to a precursor of the modern ribosome. A hybrid dimer, half polymerase and half proto-ribosome, could account for mRNA translocation before the advent of protein elongation factors.


Astrobiology ◽  
2013 ◽  
Vol 13 (4) ◽  
pp. 391-403 ◽  
Author(s):  
Marc Neveu ◽  
Hyo-Joong Kim ◽  
Steven A. Benner

Author(s):  
Olga Taran ◽  
Chenrui Chen ◽  
Tolulope O. Omosun ◽  
Ming-Chien Hsieh ◽  
Allisandra Rha ◽  
...  

The RNA world hypothesis simplifies the complex biopolymer networks underlining the informational and metabolic needs of living systems to a single biopolymer scaffold. This simplification requires abiotic reaction cascades for the construction of RNA, and this chemistry remains the subject of active research. Here, we explore a complementary approach involving the design of dynamic peptide networks capable of amplifying encoded chemical information and setting the stage for mutualistic associations with RNA. Peptide conformational networks are known to be capable of evolution in disease states and of co-opting metal ions, aromatic heterocycles and lipids to extend their emergent behaviours. The coexistence and association of dynamic peptide and RNA networks appear to have driven the emergence of higher-order informational systems in biology that are not available to either scaffold independently, and such mutualistic interdependence poses critical questions regarding the search for life across our Solar System and beyond. This article is part of the themed issue ‘Reconceptualizing the origins of life’.


2020 ◽  
Author(s):  
David M. Fialho ◽  
Suneesh C. Karunakaran ◽  
Katherine W. Greeson ◽  
Isaac Martínez ◽  
Gary B. Schuster ◽  
...  

AbstractThe mechanism by which genetic polymers spontaneously formed on the early Earth is currently unknown. The RNA World hypothesis implies that RNA oligomers were produced prebiotically, but the demonstration of this process has proven challenging. Alternatively, RNA may be the product of evolution and some, or all, of its chemical components may have been preceded by functionally analogous moieties that were more readily accessible under plausible early-Earth conditions. We report a new class of nucleic acid analog, depsipeptide nucleic acid, which displays several properties that make it an attractive candidate for the first informational polymer to arise on the Earth. The monomers of depsipeptide nucleic acids can form under plausibly prebiotic conditions. These monomers oligomerize spontaneously when dried from aqueous solutions to form nucleobase-functionalized depsipeptides. Once formed, these depsipeptide nucleic acid oligomers are capable of complementary self-assembly, and are resistant to hydrolysis in the assembled state. These results suggest that the initial formation of primitive, self-assembling, informational polymers may have been relatively facile.


Sign in / Sign up

Export Citation Format

Share Document