Notes on Genus: Marnavirus

icosahedra

Type member: Heterosigma akashiwo RNA virus

Contents

• Members of this Genus
• General Description
• Morphology
• Electron Micrograph
• Genome
• Genus Genomic Organization
• Genome Map
• Type Member Genomic Organization
• All Known Sequences
• Curated Sequences

General Description

The genus is the only member of the family Marnaviridae and currently consists of only one virus. Its genome features place it in the picorna-like superfamily but not within any of the currently recognised families. The virus infects a marine photosynthetic protist (Rhaphidophyte) and the name is derived from the Latin mare (sea) and RNA (for the genome).

Morphology

Virions isometric (icosahedral), not enveloped, about 25 nm in diameter.

Genome

Monopartite positive sense single-stranded RNA c. 8.5 kb in length, with a 3'-polyA tail.

Genus Genomic Organization

The RNA encodes a single polyprotein that is subsequently processed into the functional products. The major structural proteins are encoded near the C-terminus.

Type Member Genomic Organization

The genome of about 8,600 nucleotides is translated into a single polyprotein, which is subsequently processed into fuctional products. These have not been completely characterised but helicase, protease and RNA polymerase motifs have been identified in the N-terminal two thirds of the polyprotein and at least 2 structural proteins are at the C-terminus.