Shunting and Controlled Reinitiation: The Encounter of Cauliflower Mosaic Virus with the Translational Machinery

CaMV belongs to the caulimoviridae, the only group ofcomplex plant pararetroviruses. The replication ofcaulimoviridae is closely related to that of the animalretroviruses; however, the exception is that their genomeaccumulates in the host nucleus as an episome rather thanas an integrate and that the extracellular virions containDNA rather than RNA. The genomes of CaMV and othermembers of caulimoviridae (Fig. 1) contain a module including a Zn-finger-containing capsid (GAG)-, a protease(PR)-, and a reverse transcriptase/RNase H (RT/RH)gene, related to a similar module in retroviruses and retrotransposons. An additional module includes genes typicalfor plant RNA viruses responsible for cell-to-cell movement (MOV) and insect transmission (for CaMV: aphidtransmission, ATF) functions. CaMV also codes for aninteresting multifunctional protein, trans-activator/viroplasmin (TAV), involved in sublocalization of virus production within viroplasm and translational control...