Absence of transcriptase activity or transcription-inhibiting ability in defective interfering particles of vesicular stomatitis virus.

Defective interfering particles of New Jersey serotype VSV were found to contain very little or no virion transcriptase activity. Furthermore no VSV transcriptase activity was observed in cells treated with cycloheximide and infected with DI. Cells infected with DI together with standard infectious virus and cycloheximide showed little or no DI interference with standard virion primary transcription, whereas double infection in the absence of cycloheximide exhibited strong DI interference with replication of standard virus genome RNA. We present a model of DI interference based upon competition at the level of viral RNA replication.