Cloning And Sequence Analysis Of P3 Gene Vaccine Strain Of Foot-and-Mouth Disease Viruses Type O

RNA was extracted from vaccine strains of Food and mouth virus(FMDV) of FMDV/O/NMxw/10/99 and FMDV/O/NMzg/7/99 that were propagatet by neonate rats.The 3ABC and 3D-3,UTR gene fragments were amplified by RT-PCR method. then their fragments were cloned and sequenced in the research.The metered nucleotide sequence was splicing through DNAStar software,the P3 whole genic series was obtained,and the length are all 2691nt, encoding 897aa.The 3A,3B,3C and the 3D genes respectively contains 429,213,639,1410nt, respectively encoding 143,71,213 and 470aa.Two strains 3A genes on 276-305 be short of the 30 nt,10 amino acids.There is terminate codon TAA of the whole ORF at the 3D coding region termination. The P3 nucleotide and amino acids sequence homology between O/NMxw/10/99 and O/NMzg/7/99 respectively is 95.4%,97.3%. Between NMxw/10/99,NMzg/7/99 and the reference sequence Chu-Pei,Yunlin/97,the nucleotide and amino acids sequence homology respectively is 94.8%～96.2%,97.3%～98.2%,they compared with reference sequence SAR/2000,JPN/2000,Tibet/CHA/99,TAW/99 B0V,AKS58,Asia1/YNBS/58,C3/Argentina/85 and A12/119/Kent/UK/32,the nucleotide sequence homology is from 84.7% to 86.9%,the amino acids sequence homology is from 92.0% to 93.9%.In each gene,the 3A gene mutation rates are the tallest.The 3B,3C and 3D gene mutation rates are low,the sequence is more conservative,this have the certain relationship with the respective function.In the P3 coding region the conversion rate of the A-G and C-T is higher,it is a focus nucleotide of mutation point,and it is one of the factors that affect the amino acids stability.