[Construction and sequencing of full-length cDNA of peste des petits ruminants virus]

To develop a reverse genetics system of Peste des petits ruminants virus(PPRV), five pairs of oligonucleotide primers were designed on the basis of the full-length genomic sequence of PPRV Nigeria 75/ 1 strain. Using RT-PCR technique, five over-lapping cDNA fragments, designated as JF1, JF2, JF3, JF4 and JF5, respectively, were amplified, followed by cloning into pcDNA3.1(+)vector. An AscI restriction enzyme site and a T7 promoter sequence were introduced immediately upstream of 5'-end, while a PacI restriction enzyme site was engineered downstream of 3'-end. Using pok12 as a plasmid vector, the full-length cDNA clone pok12-PPRV of Nigeria 75/1 was assembled by connecting the five cDNA fragments via the unique restriction endonuclease site of PPRV genome. The resultant nucleotide sequence of the PPRV Nigeria 75/1 strain in the study was compared with other members of genus morbillivirus, and phylogenetic analysis was used to examine the evolutionary relationships. The results showed that PPRV Nigeria 75/ 1 was antigenically closely related to Rinderpest virus and Measles virus. Successful construction of full-length cDNA clone of PPRV Nigeria 75/1 strain lays the basis rescuing PPRV effectively and enables further research of PPRV at molecular level.