Stabilization of a full-length infectious cDNA clone for duck Tembusu virus by insertion of an intron.

Duck Tembusu virus (DTMUV) belongs to the genus Flavivirus, family Flaviviridae. In our previously study, a full-length cDNA clone of DTMUV was constructed, however, it is prone to mutation during genetic engineering due to the prokaryotic toxicity of viral protein, which is also a common feature for flavivirus. In this study, we reported an intron-containing full-length cDNA clone for a clinical strain CQW1, the intro (133bp) was inserted into nonstructural protein 1 of DTMUV at 192 site. This intron-containing full-length cDNA clone was stably propagated in Escherichia coli without prokaryotic toxicity, and recombinant virus was produced by direct transfection of plasmids. Besides, this cDNA clone-derived recombinant virus showed similar properties in comparison with parent virus both in vitro and in vivo. It's convenient and efficient, making it a useful platform for the subsequent research of reverse genetics of flavivirus.