Genomic Sequencing of S1 Strain of a Porcine Reproductive and Respiratory Syndrome Virus Isolate

Four gene fragments of S1 strain of porcine reproductive and respiratory syndrome virus were amplified by RT-PCR and cloned into the pCR-XL-TOPO vector for sequencing. Authentic 5′ and 3′ terminal fragments of S1 strain were obtained by 5′ -Full RACE Core Set and 3′ -Full RACE Core Set and cloned into the pMD-18T vector and sequenced. The complete nucleotide sequence of S1 strain genome was obtained by sequential splicing of each fragment. The results showed that the genome of S1 strain was 15441 bp in length, containing nine open reading frames (ORFs), with 189 nt in the 5’ UTR and 181 nt in the 3’ UTR, including 30 nt poly (A) tail. The genome of PRRSV S1 strain showed 99.5%, 99.6% and 90.8% of nucleotide identity with ATCC VR-2332, BJ-4 and CH-1a, respectively.