Notes on Genus: Umbravirus

enveloped bacilliform (?)

Type member: Carrot mottle 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 Umbravirus contains viruses that, in nature, depend upon a specific helper virus (commonly a luteovirus) for their (persistent aphid) transmission. The name umbra (Latin for a shadow) reflects this property. Structures seen in infected cells (enveloped and bullet shaped) may or may not be virions.

Morphology

Virions may be enveloped and bullet shaped but the structures found in plant cells are not clearly understood and may be cytopathological structures involved in virus replication. No structural protein has been identified from sequence data.

Genome

Single stranded, positive sense RNA, about 4500 nucleotides long. The 3' terminus has no poly(A) tract.

Genus Genomic Organization

In the members sequenced there are four open reading frames:

1.	31-37 kDa	Replication protein
2.	64 kDa	Polymerase, probably expressed as a 90-100 kDa translational frameshift fusion with the product of ORF1
3.	27-29 kDa	Putative long distance movement protein, probably expressed from a subgenomic RNA
4.	28-31 kDa	Cell-to-cell movement protein, probably expressed from a subgenomic RNA

Type Member Genomic Organization

There are four open reading frames:

1.	37 kDa	Replication protein
2.	64 kDa	Polymerase, probably expressed as a 96 kDa translational frameshift fusion with the product of ORF1
3.	29 kDa	Putative long distance movement protein, probably expressed from a subgenomic RNA
4.	31 kDa	Cell-to-celll movement protein, probably expressed from a subgenomic RNA

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