Molecular cloning and nucleotide sequence studies on enterovirus type 70.

The molecular cloning of enterovirus type 70 (EV70) was achieved using the hybrid (vRNA:cDNA) cloning strategy. Recombinant plasmids containing EV70 sequences were identified by hybridization in situ. EV70 cDNAs were characterized by optical and Smith-Birnstie1 (1976) restriction mapping techniques. Hybridization and restriction mapping data showed that a series of overlapping, subgenomic EV70 clones spanning 7.25Kbp had been produced. EV70 cDNAs were isolated and fragmented by subsequent restriction or ultra-sonic shearing methods. cDNA fragments produced by these methods were sub-cloned into bacteriophage M13 vectors and their nucleotide sequences determined by the dideoxynucleotide chain-termination method (Sanger et al, 1977). The results showed that considerable homology existed between EV70 and poliovirus. The homology was sufficient to permit identification and delineation of EV70 infected-cell polypeptides by analogy with the po1ioviruses. Many aspects of the biology of EV70, therefore, could be correlated with specific regions of the genome.