Element:PVCV

Description Petunia vein clearing virus (PVCV) is the type species of the Petuvirus genus of Caulimoviridae plant virus family and represents the only member of this genus because of none new tentative species has been yet reported [International Committee on the Taxonomy of Viruses (ICTV), Fauquet et al. 2005]. This pararetrovirus was first detected in Petunia x hybrida cv. Himmelsroeschen by electron microscopy (Lesemann and Casper 1973) but has subsequently been reported in other Petunia species (Richert-Pöggeler et al. 2002). According to Llorens et al 2009, Petuvirus genus and consequently PVCV element, although falls more-or-less close to Class 1, constitutes an independent class (Class 4) in the phylogenetic study. PVCV consists of unenveloped isometric particles of 43-46 nm in diameter (for more details also see ICTVdb) which genome, of circular dsDNA 7206 bp long, is organized into a large Open reading frame (ORF) (even if the first sequence deposited by Richert-Pöggeler and Shepherd 1997 showed two overlapping ORFs). The long encoded polyprotein of about 238 kD contains a putative movement protein typical of caulimoviruses, a putative integrase (INT) region similar to those coded by LTR retrotransposons, and the Ty3/Gypsy-like coat (gag) and pol domains (protease, reverse transcriptase and RNaseH) (Richert-Pöggeler and Shepherd 1997; Harper et al. 2002). In contrast to other pararetrovirus which present a large consensus RNA-binding sequence associated to the putative COAT-gag region -due to the presence of an additional cysteine at the -2 position (C-X-C-X2-C-X4-H-X4-C )-(Hull 1996; Bouhida et al. 1993), PVCV contains the same cys-motif observed in the retroelement consensus RNA-binding sequence (C-X2-C-X4-H-X4-C) (Richert-Pöggeler and Shepherd 1997). The INT protein of the retroviruses and retrotransposons is known to be the only protein required for the integration process, therefore the presence of a probable integrase function in the genome of PVCV suggests that it may exist both as a transmissible caulimovirus and as a retrotransposon potentially able to transpose in the Petunia genome (Richert-Pöggeler and Shepherd 1997). In contrast to some other caulimoviruses, PVCV genome lacks both the transactivator (TAV) and aphid transmission functions (ATF). The absence of an insect acquisition gene may explain the limited hosts range in nature (it has been found only in Petunia spp. in which the virus is transmitted vertically and horizontally, Richert-Pöggeler and Shepherd 1997; Richert-Pöggeler et al. 2002; Richert-Pöggeler et al. 2003). Structure Figure not to scale. If present, long terminal repeats (LTRs) have been highlighted in blue. Amino acid motifs noted with lines indicate the conserved residues in each protein domain, abbreviations below mean: MA=matrix PR=protease DU or DUT=dUTPase TM=transmembrane TAV or IBMP=transactivator/viroplasmin or inclusion body matrix protein CA=capsid RT=reverse transcriptase INT=Integrase CHR=chromodomain NC=nucleocapsid RH=RNaseH SU=surface MOV=movement protein PPT=polypurine tract PBS=primer binding site ATF=aphid transmission factor VAP=virion associated protein Related literature

Genbank accession: 14575752 Clade: ' Cluster or genus: Petuvirus Branch or class: Class 4 Family: Caulimoviridae System: LTR retroelements Host: Explore the Tree Life Project Petunia spp Wikimedia commons, courtesy of Kor!An author Browse all elements