Stirrups K, Shaw K, Evans S, Dalton K, Cavanagh D, Britton P
Division of Molecular Biology, Compton Laboratory, Newbury, United Kingdom.
Adv Exp Med Biol. 1998;440:259-64. doi: 10.1007/978-1-4615-5331-1_33.
Coronavirus defective RNA (D-RNA) vectors could be developed to deliver selected genes for the production of recombinant coronavirus vaccines. An IBV D-RNA, CD-61, derived from a naturally occurring IBV Beaudette D-RNA, CD-91, is being developed as a D-RNA vector for IBV. In order to use CD-61 as a vector it will require rescue by heterologous strains in addition to Beaudette. Rescue will be determined by recognition of replication and packaging signals within the D-RNA by the helper virus. The 5' and 3' UTRs are believed to contain sequences involved in replication and transcription. The 5' and 3' UTRs of six strains of IBV have been sequenced and experiments performed using six strains of helper virus for rescue of CD-61 to determine whether rescue correlates with sequence conservation within the 5' and 3' UTRs. Results indicate that all strains of helper virus rescued the D-RNA to varying degrees. Sequence comparisons show a high degree of sequence identity in the UTRs, but enough strain differences exist to be used as markers. The 5' and 3' UTRs of the D-RNAs rescued by the heterologous strains were also sequenced and leader switching between the helper virus and the Beaudette leader on the D-RNAs was observed.
冠状病毒缺陷RNA（D-RNA）载体可用于递送选定基因，以生产重组冠状病毒疫苗。一种源自天然存在的传染性支气管炎病毒（IBV）博德特D-RNA（CD-91）的IBV D-RNA（CD-61）正在被开发为IBV的D-RNA载体。为了将CD-61用作载体，除了博德特毒株外，还需要通过异源毒株进行拯救。拯救将由辅助病毒对D-RNA内复制和包装信号的识别来决定。5'和3'非翻译区（UTR）被认为包含参与复制和转录的序列。对六种IBV毒株的5'和3'UTR进行了测序，并使用六种辅助病毒毒株进行了拯救CD-61的实验，以确定拯救是否与5'和3'UTR内的序列保守性相关。结果表明，所有辅助病毒毒株都不同程度地拯救了D-RNA。序列比较显示UTR中存在高度的序列同一性，但也存在足够的毒株差异可作为标记。对异源毒株拯救的D-RNA的5'和3'UTR也进行了测序，并观察到辅助病毒与D-RNA上博德特前导序列之间的前导序列切换。
