High-frequency leader sequence switching during coronavirus defective interfering RNA replication. |
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Authors: | S Makino and M M Lai |
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Institution: | Department of Microbiology, University of Southern California, School of Medicine, Los Angeles 90033. |
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Abstract: | A system was developed that exploited defective interfering (DI) RNAs of coronavirus to study the role of free leader RNA in RNA replication. A cDNA copy of mouse hepatitis virus DI RNA was placed downstream of the T7 RNA polymerase promoter to generate DI RNAs capable of extremely efficient replication in the presence of a helper virus. We demonstrated that, in the DI RNA-transfected cells, the leader sequence of these DI RNAs was switched to that of the helper virus during one round of replication. This high-frequency leader sequence exchange was not observed if a nine-nucleotide stretch of sequence (UUUAUAAAC) at the junction between the leader and the remaining DI sequence was deleted. This observation suggests that a free leader RNA generated from the genomic RNA of mouse hepatitis virus may participate in the replication of DI RNA. |
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