RNA-dependent RNA polymerase (RdRp) in the family Mayoviridae of positive-sense single-stranded RNA [(+)ssRNA] viruses
This group contains the RdRp of RNA viruses belonging to the family Mayoviridae, order Martellivirales. The Mayoviridae family consists of two genera, Idaeovirus and Pteridovirus. The genus Idaeovirus contains Raspberry bushy dwarf virus (RBDV), named after the host with which it was first associated (red raspberry, Rubus idaeu) and the disease which is characterized by bushiness (stunting and proliferation of canes); RBDV has recently been found causing an infection in grapevines. RBDV occurs in all tissues of the plant, including seed and pollen, and is transmitted in association with pollen, both vertically to the seed and horizontally to the pollinated plant; this is the only known method of natural spread of RBDV. The RdRp domain displays a right hand with three functional subdomains, called fingers, palm, and thumb. All RdRps contain conserved polymerase motifs (A-G), located in the palm (A-E motifs) and finger (F-G) subdomains. All these motifs have been implicated in RdRp fidelity such as processes of correct incorporation and reorganization of nucleotides.
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