viroids - obelisks

see also:

• microbiology
• antiviral agents
• prions
• plasmids
• viruses

• in contrast to viruses, viroids contain RNA but co-opt eukaryotic host RNA polymerases for their replication and lack protein-coding capacity

• “obelisks” are heritable viroid circular RNA based (∼1,000 nt) rod-like structures
• they lack any evident homology to characterized genomes or viromes
• the RNA codes for at least one member of a Oblin protein superfamily
• they are found in various ecological niches including in oral and faecal microbiomes
• a subset of obelisks harbors obelisk-specific hammerhead ribozyme motifs
• Streptococcus sanguinis in the mouth is a cellular host of a specific obelisk ¹⁾