A design principle for a single-stranded RNA genome that replicates with less double-strand formation

Usui, Kimihito; Ichihashi, Norikazu; Yomo, Tetsuya

A remaining unanswered question is why the 'less GC in loops' rule is valid for bacterial and fungal virus genomes, but not for other higher organisms, such as vertebrates and plants. Some (46) . During the replication of these viruses, a single-stranded RNA genome is synthesized from the double-stranded intermediate form. Therefore, the nascent strand can be synthesized as a single strand, even if it possesses a high GC content in loop. Another possibility is that RNA-binding proteins might bind and inhibit the hybridization between a template and a newly synthesized strand. SsRNA viruses of vertebrates include clinically important viruses, such as coronaviruses and hepatitis C virus. Although further investigations are required, the discovery of the mechanisms that inhibit dsRNA formation in vertebrates might provide a new drug target for ssRNA virus infection.