Evidence for secondary structure within the virion RNA of echovirus 22

Abstract

Phenol-extracted echovirus 22 virion RNA is infectious, but unlike poliovirus virion RNA, it resists digestion with pancreatic RNase and nuclease P-1, a 3' exonuclease selective for single-stranded RNA. These data indicate the presence of an enzyme-resistant portion somewhere in the RNA molecule and suggest that it is a double-stranded or base-paired region distant from the unblocked 3' terminus. Equilibrium density gradient centrifugation of native echovirus 22 virion RNA results in a single peak with a density of 1.63 g/cm3. When sheared before centrifugation, the molecule is resolved into two RNA species: one with an approximate density of 1.70 to 1.71 g/cm3, as is observed also for single-stranded poliovirus virion RNA, and the other with a density of 1.58 to 1.59 g/cm3. Data obtained from rate zonal centrifugation may be used to calculate an approximate sedimentation coefficient corrected to water at 20°C of 34 and a molecular weight of 2.4 x 106 for the virion RNA. We propose a model for echovirus 22 RNA composed of a linear RNA molecule with a 5' hairpin.

Molecular detection and identification of enteroviruses using enzymatic amplification and nucleic acid hybridization

“…Our observation that EV22, the only one of the 41 enteroviruses examined, was not detected by the El and E2 primers is consistent with other data which suggest that EV22 does not correspond to the enteroviral paradigm (11,35,40). EV22 RNA is not detectable with either CVB3 or PV1 sequences, both of which are prototypic of the enteroviral genome (30).…”

Echovirus 22 is an atypical enterovirus

“…In this report, we confirm and greatly extend observations of others (11,25,58,62,65,73,81,83) that EV22 is an FIG. 6.…”

“…Radioactive EV22 and CVB3 cDNAs were synthesized by using random primers and then used to probe Northern blots of CVB3, EV22, and EMCV RNAs. The RNA genome of EV22 has been reported to possess an unusually large region of secondary structure (62). To control for the possibility that reverse transcriptase might not be able to transcribe through the snap-back region, we prepared cDNA from both native and denatured RNA.…”

Enzymatic RNA amplification of the enteroviruses

“…primers are less homologous to these seroty fore, less efficient in annealing and priming sequences of echoviruses 2 and 22 are not kn 22 is known to be dissimilar in many respe EVs (19). We have shown weaker hybridizati and coxsackievirus probes to echovirus 2, serotypes (17).…”