RNAs from two independently isolated defective interfering particles of Sindbis virus contain a cellular tRNA sequence at their 5' ends.

Defective interfering (DI) particles are deletion mutants that interfere specifically with the replication of homologous standard virus. We have determined the 5'-terminal nucleotide sequences of two DI RNA populations by the following methods: (i) cloning of the cDNA from one of the DI RNA populations and sequencing a representative clone, and (ii) using both DI RNA populations as templates for preparing primer-directed cDNA transcripts and sequencing these transcripts. The 5' terminal sequences of the two DI RNA populations were not derived from standard Sindbis viral RNA but were almost identical to those of a cellular tRNAAsp.