Expression of the Genome of Defective Interfering Pseudorabies Virions in the Presence or Absence of Helper Functions Provided by Standard Virus

The synthesis of virus RNA and proteins in cells infected with two populations of defective virions [Pr(I)53 and Pr(2)53] which vary in the overallcornposition of their DNA, but which share some structural and biological characteristics, have been examined. The experiments were done under two sets of conditions: (I) at high multiplicity of infection. In this case, practically all the cells in the cultures were co-infected with defective and infectious virions; (2) at low multiplicity of infection. In this case, 75 % of the cells in the cultures were infected with defective virions only and 25 % were co-infected with defective and infectious virions. The relative abundance of RNA classes complementary to different regions of the virus genomes that were synthesized under various conditions of infection were determined by the Southern (i 975) technique; the synthesis of virus proteins was determined by poly-acrylamide gel electrophoresis (PAGE). In cells co-infected with standard and defective virions, RNA complementary to the regions that are reiterated in the de-fective genomes is present in larger amounts than i cells infected with standard virions alone, indicating that the genomes of the defective virions are transcribed