Tolecusatellitidae

Satellite virus: Replicated and packaged by helper Begomoviruses or Mastrevirus

GENOME

Circular, single-stranded DNA genome of 700 to 1,350 nucleotides that have no sequence identity to their helper begomoviruses. Contains an adenine rich region, and a satellite conserved region (SCR).

GENE EXPRESSION

The genome encodes either none or one protein.



h4. REPLICATION

NUCLEAR

  1. Virus penetrates into the host cell.
  2. Uncoating, the viral ssDNA genome penetrates into the nucleus.
  3. The ssDNA is converted into dsDNA with the participation of cellular factors.
  4. bidirectional dsDNA transcription from the IR promoter produces viral mRNAs and translation of viral proteins.
  5. Replication is initiated by cleavage of the(+)strand by REP, and occurs by rolling circle producing ssDNA genomes.
  6. These newly synthesized ssDNA can either
    a) be converted to dsDNA and serve as a template for transcription/replication
    b) be encapsidated by CP and form virions released from the cell by budding
    c) be transported outside the nucleus, to a neighboring cell through plasmodesmata (cell-cell movement) with the help of viral movement proteins.