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The proposed genus "Sapelovirus" consists of three
species (proposed names in parentheses), Porcine enterovirus A ("Porcine
sapelovirus"), SV2-like
viruses ("Simian sapelovirus") and duck picornavirus TW90A ("Avian
sapelovirus"). The name Sapelovirus is derived from Simian, Avian and
Porcine Entero-Like viruses.
The three sapelovirus species may be distinguished
by i) different host species; and ii) sequence diversity. For
example in the VP1 gene there is less than 50% amino acid identity
between the species (Table 1; Fig. 1). The simian "sapeloviruses"
(which probably belong to three [sero]types) have probably undergone
some complicated recombination events as can be seen from a
comparison of sequences in different genome regions (Figs. 1 and 2).
The complete genome sequences of three
entero-like viruses have been determined, porcine enterovirus 8
(PEV-8) (currently classified with the enterovirus species
Porcine enterovirus A),
simian virus 2 (SV2) (an unassigned member of the genus
Enterovirus)
and an unclassified duck picornavirus (DPV)(Krumbholtz
et al.,
2002; Oberste et al.,
2003; Tseng and Tsai, 2007). These three viruses are related to each
other (clustering together phylogenetically) (Figs. 3 and 4) and
broadly resemble the enteroviruses. However, they are distinct for a
number of reasons: i) they are all predicted to share a type IV
(hepatitis C virus-like) internal ribosome entry site (IRES) (Hellen
and de Breyne, 2007); ii) possess a Leader polypeptide; and iii)
have very divergent 2A, 2B and 3A sequences such that cannot be
directly compared with the same enterovirus proteins. Genetic
distances from the enteroviruses in the P1cap, 2C, 3Cpro
and 3Dpol regions are large (31-37%; 35-45%,
39-52%, 52-58%, respectively).
Tables and figures to appear
soon...
ReferencesHellen, C.U. and
de Breyne, S. (2007). A distinct group of hepacivirus/pestivirus-like
internal ribosomal entry sites in members of diverse picornavirus
genera: evidence for modular exchange of functional noncoding RNA
elements by recombination. J. Virol. 81: 5850-5863.
Kaku, Y., Sarai, A. and Murakami, Y. (2001).
Genetic reclassification of porcine enteroviruses. J. Gen. Virol.
82: 417-424.
Krumbholz, A., Dauber, M., Henke, A., Birch-Hirschfeld,
E., Knowles, N.J., Stelzner, A. and Zell, R. (2002). Sequencing of
porcine enterovirus groups II and III reveals unique features of
both virus groups. J. Virol. 76: 5813-5821.
Oberste, M.S., Maher, K. and Pallansch, M.A.
(2003). Genomic evidence that simian virus 2 and six other simian
picornaviruses represent a new genus in Picornaviridae. Virology
314: 283-293.
Tseng, C.-H. and Tsai, H.-J. (2007). Sequence
analysis of a duck picornavirus isolate indicates that it together
with porcine enterovirus type 8 and simian picornavirus type 2
should be assigned to a new picornavirus genus. Virus Res 129:
104-114.
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