| ObjectiveIn recent years, disease caused by the Echovirus increased gradually, the lack of complete system monitoring data on the pathogens, knowledge and the pathogen detection technology on the information of the Enterovirus. Frequent recombinant and genetic variation, new enterovirus (EV79,91, et) are appearing in hints that we should strengthen the epidemiological surveillance of enterovirus and laboratory testing, development non-intestinal virus structural coding sequence. ECHO25 (Entric Cytopathic Human Orphanviruses Type25) is the most common pathogens of viral encephalitis, there is no other information of the pandemic strain and clinical isolates of ECHO25 except JV-4, To reveal the genomic sequence characteristic of ECHO25 virus, the homology and recombination with other human enterovirus B gene, and whether the different parts of the virus genes evolved relatively independent, we sequenced the strains isolated from henan province. MethodsThe complete VP1 sequences of the 4 isolates and the whole genome sequence of HN-02 were successfully amplified by RT-PCR.The VP1 sequences were aligned with the reference strains as well as with the other Human Enterovirus B species by the neighbor-joining (NJ) algorithm as implemented in CLUSTALX 1.81 computer software. Phylogenetic were conducted using MEGA version 4.0. homology analysis of the genome was performed with the Bioedit software; Similarity analysis of the complete genome alignments was performed with the SimPlot software, using a sliding window of 200 nucleotides moving in steps of 20 nucleotides. the amino acid composition, secondary structure, the hydrophilic and surface antigen was analyzed by Protean.Results1. The nucleotide sequence identity among the 4 ECHO25 strains was 93.0%～99.0%, the amino acids homology among them was 92.4%～97.5%; HN-35 was the most variation strain, the nucleotide sequence differences with other three henan separation strains amount to 6.8%～7%. HN-01 and HN-26 strains had high degree of homology between the strains, the nucleotide homology of them was 99.0%;2. All the 4 strains belonged to the B1 genetype;3. The full length of HN-02 genome was 7428bp. Compared with the prototype strain JV-4, the entire coding region of amino acid homology was 96.5%, which difference of VP4-VP2 nucleotide vary by 18.6% to 19.2%, difference of VP1 nucleotide 19.6%; P2, P3 nucleotide differences were 17.5%,19.9%. In the VP4-VP2 interval, the HEVB vary by 20.5% to 34.3% between serotypes;4. The similarity curves showing more variation in the P1(VP4-VP2,VP1) region than in the 5'NCR or the P2, P3 region;5. The amino acid composition by nonpolar of leucine most, occupy 7.9%,the polarity of valine Second, accounting for 7.8%, The polarity of tryptophan at least, accounting for 1.5%. The secondary structure with the alpha helix is priority, followed by beta folding and beta corner, few with rules curly, the hydrophilic was high, and it had multiple potential antigen site.Conclusions1. The 4 ECHO25 strains isolated in Henan is a single genotype, and it is totally different with the prototype JV-4 strain, It has been the formation of new subtype.2. Compared with the prototype strain JV-4, HN-02 coding sequence is in silent mutation, the nucleotide variation does not affect amino acid sequence.3. The Simplot result indicate that recombination in the henan ECHO25 strain occurred, The genome evolution in the district of it were not in synchronous. |
