Notes on Genus: Capillovirus

flexuous filaments
flexuous filaments

Type member: Apple stem grooving virus

Contents

General Description

The genus Capillovirus (from the Latin capillus = a hair) is one of the genera now included in the family Betaflexiviridae. It contains viruses originally placed as tentative members of the genus Closterovirus, but which have shorter virions, a very different genome organisation and a poly(A) tail.

Morphology

Virions filamentous, not enveloped, 640 nm long and 12 nm in diameter. Nucleocapsids have 'rope-like' and 'criss-cross' patterns when stained with uranyl acetate.

Virions composed of 5% nucleic acid.

Genome

Monopartite, linear, single stranded, positive sense RNA, 6500-7500 nucleotides long. 3' terminus has a poly(A) tract.

Genus Genomic Organization

The viral RNA is translated into a polyprotein (240-270 kDa), which is subsequently processed into functional products, with the coat protein at the C-terminus. A separate protease or movement protein may also be translated directly from a different reading frame.

Type Member Genomic Organization

RNA is c. 6500 nucleotides long and is believed to be translated into a large (241 kDa) polyprotein, which is subsequently processed into functional products. A separate 36 kDa protein translated in a different reading frame is believed to be a movement protein.