Viroids: Survivors from the RNA World?

Viroids: survivors from the RNA world?

Because RNA can be a carrier of genetic information and a biocatalyst, there is a consensus that it emerged before DNA and proteins, which eventually assumed these roles and relegated RNA to intermediate functions. If such a scenario--the so-called RNA world--existed, we might hope to find its relics in our present world. The properties of viroids that make them candidates for being survivors o...

Viroids: petite RNA pathogens with distinguished talents.

Viroids are small, circular, single-stranded RNA molecules that cause several infectious plant diseases. Viroids do not encode any pathogen-specific peptides but nonetheless, the subviral pathogens replicate autonomously and spread in the plant by recruiting host proteins via functional motifs encoded in their RNA genome. During the past couple of years, considerable progress has been made towa...

Viroids: an Ariadne's thread into the RNA labyrinth.

Viroids are structurally, functionally and evolutionarily different from viruses. Despite their small, non-protein-encoding, single-stranded circular RNA genome, viroids can infect higher plants and cause certain diseases. Members of the two viroid families, Pospiviroidae and Avsunviroidae, have evolved to usurp the transcriptional machinery of their host nuclei and chloroplasts, respectively, ...

From Lisbon to the World...

Life from an RNA World

platelet serotonin levels. Curiously, both groups of rats differ noticeably from their wild-type counterparts only when confronted with an environmental or pharmacological challenge. The book then goes on to describe the interaction between the serotonin system and other neurotransmitters, particularly dopamine, in models of drug reward. Primates, like humans, have complex social lives yet can ...