Caulimoviridae (taxid:186534)

VIRION

Virions not enveloped, bacilliform (30 x 60-900 nm) or isometric (45-50 nm in diameter).

GENOME

Monopartite, open circular, double stranded DNA of 7000-8200 base pairs with discontinuities in both strands: one in the transcribed strand and one to three in the non-transcribed strand. Encode for 1 to 8 proteins.

GENE EXPRESSION

The genome encodes a genomic mRNA, which may be alternatively spliced in some genera. The genomic mRNA generally encodes multiple ORFs expressed by ribosomal shunt.

ENZYMES

• Reverse transcriptase
  • RNA-dependent DNA polymerase [RT]
  • DNA-dependent DNA polymerase [RT]
• RNAse H [RT]
• Polyprotein protease (Peptidase A3) [PRO]

REPLICATION

CYTOPLASMIC / NUCLEAR

1. Attachment of viral proteins to host receptors mediates entry into the host cell.
2. The viral dsDNA is released into the nucleus.
3. Transcribed by host RNA polymerase II.
4. mRNA translation produces viral proteins.
5. Genomic RNA is retrotranscribed into new dsDNA genomes in the cytoplasm.
6. Genomes are encapsidated by the capsid protein and form new virions.
7. The virion infects either a new cell by plasmodesmata movement, or by insect vector uptake.