The largest dsRNA segment (dsRNAl) of the chrysoviruses so far sequenced contains a single large ORF coding for RdRp. The calculated molecular mass of chrysovirus RdRps ranges from 122 to 129 kDa (Table 1). These values are consistent with those estimated by SDS-PAGE of the in vitro translation products of full-length transcripts derived from cDNAs to dsRNAls of PcV and Hv145SV. Examination of the deduced amino acid sequence of the RdRp ORF reveals the presence of the eight conserved motifs characteristic of RdRps of dsRNA viruses of simple eukaryotes (Figure 4). A comparison of the conserved motifs of chrysovirus RdRps with those of totiviruses and partitiviruses reveals that the RdRps of chrysoviruses are more closely related to those of totiviruses than to those of partitiviruses (Figure 4). This conclusion is also supported by published results of phylogenetic analysis of RdRp conserved motifs and flanking sequences of chrysoviruses and viruses in the families Totiviridae and Partitiviridae (see section on 'Evolutionary relationships').
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