Citrus psorosis virus RNA 1 is of negative polarity and potentially encodes in its complementary strand a 24K protein of unknown function and 280K putative RNA dependent RNA polymerase

Recent advances in Citrus psorosis virus

“…The circular morphology of CPsV virions suggests the possibility of a panhandle structure formed by base pairing between the two terminal regions of each RNA [19]. The first 75nt of the CPsV RNA1 terminal regions show 41 % complementarity, a value similar to that described for the RNAs of MiLBVV and of the lettuce bigvein varicosavirus [39]. However, Naum-Ongania et al [39] observed that secondary structure predictions do not support significant complementary between the termini of the viral RNAs to afford panhandle formation, or of a ''Corkscrew'' structure as proposed for Influenza A virus and MiLBVV.…”

“…The first 75nt of the CPsV RNA1 terminal regions show 41 % complementarity, a value similar to that described for the RNAs of MiLBVV and of the lettuce bigvein varicosavirus [39]. However, Naum-Ongania et al [39] observed that secondary structure predictions do not support significant complementary between the termini of the viral RNAs to afford panhandle formation, or of a ''Corkscrew'' structure as proposed for Influenza A virus and MiLBVV. None of these structures were predicted by the MFOLD program for any of the CPsV RNAs [39].…”

“…RNAs 1, 2 and 3 of the isolate CPV-4 have been sequenced [5,39,58,59]. RNA extracted from citrus infected tissue is assayed for the presence of CPsV sequences by RT-PCR, cDNA copies are made and amplified for analyses.…”

“…RNA 1 is * 8,184 nt in size and its viral complementary strand (vcRNA) has two open-reading frames (ORFs), The first ORF potentially encodes a 24 kDa protein of unknown function and, separated by an intergenic region of 109 nt, a second ORF potentially coding for a 280 kDa protein contains between positions 635 and 874 the core polymerase module with the five conserved motifs proposed to be part of the RNA dependent RNA polymerase (RdRp). vcRNA 2 (*1,644 nt) carries one ORF coding for a 54 kDa protein of unknown function, which includes a motif resembling a nuclear localization signal (NLS), and vcRNA 3 (*1,454 nt) codes for the CP of 48, 6 kDa [5,39,58,59].…”

“…In the 3 0 -terminal untranslated region of RNA2 there is a putative polyadenylation signal [59], was also found in the 3 0 UTR of the positive strand of RNA3 [58] and RNA1 [39]. The 3 0 -terminal regions of the three CPsV RNAs are very similar, while their 5 0 -terminal regions in contrast, differ considerably in sequence.…”