Adenovirus-Associated Virus Multiplication VIII. Analysis of In Vivo Transcription Induced by Complete or Partial Helper Viruses

Abstract

We have analyzed ribonucleic acid (RNA) synthesized in KB cells co-infected with adenovirus-associated virus (AAV) type 2 and either adenovirus type 2 (Ad2) or herpes simplex virus type 1 (HSV-1). With either type of helper virus, synthesis of AAV RNA was readily detected by deoxyribonucleic acid (DNA)-RNA hybridization. As is the case for AAV RNA synthesized with helper Ad2, the AAV RNA synthesized with HSV-1 as helper annealed only to the thymidine-rich (minus) AAV DNA strand. In addition, AAV RNA synthesized with either type of helper (i) contained similar nucleotide sequences as determined by hybridization inhibition tests and (ii) had a mean molecular weight of approximately 7.5 × 10 5 based on sedimentation in dimethylsulfoxide-sucrose gradients. These experiments suggest that the restricted helper function of HSV-1 is not due to abnormal transcription of the AAV genome. Since the mean molecular weight of AAV RNA is equivalent to 40 to 50% of the AAV genome, as few as two or three AAV RNA species may be transcribed in vivo. In contrast to adenovirus RNA, cleavage of AAV RNA after transcription was not observed.