Tombusvirus infections are often associated with satellite (sat) RNAs, which are subviral molecules sharing no significant sequence homology with the helper genome other than some specific nucleotide stretches. We have characterized a new satRNA (satRNA L) associated with Tomato bushy stunt virus (TBSV). satRNA L consists of a single-stranded RNA 615 nucleotides in size, lacks significant open reading frames and has no sequence homology with the helper genome other than in the 5'-proximal seven nucleotides and in a central region that is also conserved in all tombusvirus genomic, defective interfering and satellite RNAs. Secondary structure analysis shows the presence of high order domains similar to those described for other tombusvirus RNAs. satRNA L does not modify the symptoms induced by TBSV. The accumulation of satRNA L is dependent on the temperature. siRNAs originate from both positive and negative polarities and may have a role in satRNA accumulation, whereas shorter-than-unit-length molecules are not related to a silencing mechanism. Coinoculation of satRNA L with transcripts of Carnation Italian ringspot virus (CIRV) and Cymbidium ringspot virus (CymRSV) shows that CIRV, but not CymRSV, supports satRNA L replication. The sequence region responsible for supporting satRNA L replication maps within the 5'-UTR and the ORF1 N-terminal region of CIRV genome. satRNA L can be replicated if coinoculated with CymRSV virus particles, suggesting that the coat protein has a role in the early stages of replication. The different intracellular replication site of CIRV and CymRSV may account for their diverse capability to replicate satRNA L.
Studies on the replication of a TOMBUSVIRUS SATELLITE RNA
RUBINO L;RUSSO M
2010
Abstract
Tombusvirus infections are often associated with satellite (sat) RNAs, which are subviral molecules sharing no significant sequence homology with the helper genome other than some specific nucleotide stretches. We have characterized a new satRNA (satRNA L) associated with Tomato bushy stunt virus (TBSV). satRNA L consists of a single-stranded RNA 615 nucleotides in size, lacks significant open reading frames and has no sequence homology with the helper genome other than in the 5'-proximal seven nucleotides and in a central region that is also conserved in all tombusvirus genomic, defective interfering and satellite RNAs. Secondary structure analysis shows the presence of high order domains similar to those described for other tombusvirus RNAs. satRNA L does not modify the symptoms induced by TBSV. The accumulation of satRNA L is dependent on the temperature. siRNAs originate from both positive and negative polarities and may have a role in satRNA accumulation, whereas shorter-than-unit-length molecules are not related to a silencing mechanism. Coinoculation of satRNA L with transcripts of Carnation Italian ringspot virus (CIRV) and Cymbidium ringspot virus (CymRSV) shows that CIRV, but not CymRSV, supports satRNA L replication. The sequence region responsible for supporting satRNA L replication maps within the 5'-UTR and the ORF1 N-terminal region of CIRV genome. satRNA L can be replicated if coinoculated with CymRSV virus particles, suggesting that the coat protein has a role in the early stages of replication. The different intracellular replication site of CIRV and CymRSV may account for their diverse capability to replicate satRNA L.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
