Pr

1
NIa
P1
HC-Pro
VPg
P1 HC-Pro P3
CI
NIa NIb CP
Poly (A)
6K1
6K2
Figure X1. PPV genome organization. The RNA
genome is represented as a horizontal line, with
VPg and poly(A) at the 5 and 3 end,
respectively. The genome contains a single large
open reading frame translated into a unique
polyprotein (boxed), that is later cleaved
(vertical lines) into 9 functional units. The
names of the 9 viral proteins are indicated
within the corresponding boxes, except for 6K1
and 6K2 which are indicated below. The viral
proteinases (NIa, P1 and HC-Pro) and their
cleavage site(s) (arrows) are represented above.
The N- and C-terminal parts of NIa correspond to
the VPg and proteinase domains of NIa,
respectively. The three analyzed regions A, B and
C are represented as grey boxes from 5 to
3. Functions of viral proteins P1 trypsin-like
serine proteinase, C-terminal self-cleavage and
symptom expression HC-Pro papaïn-like cysteine
proteinase, C-terminal self-cleavage,
aphid-transmission, systemic movement,
suppression of gene silencing P3 unknown 6K1
unknown CI ATPase/ RNA helicase, cell-to-cell
movement 6K2 anchoring the viral replication
complex to membranes NIa the N-terminal domain
is VPg, involved in genome replication, and the
C-terminal domain is a trypsin-like serine
proteinase acting both in cis and trans NIb
RNA-dependent RNA-polymerase (RdRp) CP coat
protein, virus assembly, aphid transmission,
cell-to-cell and systemic movement.