Adeno-associated virus RNA transcription in vivo.
We have studied RNA transcripts of the defective parvovirus, adeno-associated virus (AAV) present in poly(A)rich and poly-(A)free fractions of nuclear and cytoplasmic RNA prepared from cells infected together with a helper adenovirus. Cytoplasmic poly-(A)rich RNA contains three overlapping spliced AAV RNAs having sizes of 3.9 X 10(3), 3.3 X 10(3) and 2.3 X 10(3) bases respectively. The nuclear precursors of these RNAs appear to be the coterminal unspliced poly(A)-rich RNAs containing 4.2 X 10(3), 3.6 X 10(3) and 2.6 X 10(3) bases respectively. These unspliced RNAs were also found in the cytoplasm. The nuclear poly(A)-free RNA contained a heterogenous population of AAV RNAs that were generally smaller than 2.3 X 10(3) bases. In addition, the Hirt pellet fraction of the nuclear RNA contained two discrete AAV poly(A)-free RNAs having sizes of 2.5 X 10(3) and 2.8 X 10(3) bases. The 4.2 X 10(3) and 3.6 X 10(3)-base unspliced RNAs are more abundant than the coterminal 3.9 X 10(3) and 3.3 X 10(3)-base spliced RNAs whereas the 2.3 X 10(3)-base spliced RNA is much more abundant than the 2.6 X 10(3)-base unspliced RNA. Thus, the cytoplasmic abundance of the AAV spliced RNAs appears to be controlled in part by the post-transcriptional events of splicing or message stability. We also analysed the effects of AAV defective-interfering genomes upon AAV transcription. These studies showed that when synthesis of standard AAV genomes was inhibited more than 10-fold by defective-interfering genomes there was no significant effect on the types or amounts of AAV RNA transcripts which accumulated. These observations indicate that interference by defective-interfering genomes occurs mostly at the level of DNA replication rather than transcription.
D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D004279:DNA, Viral; D000229:Dependovirus / Q000235:genetics / Q000378:metabolism*; D004587:Electrophoresis, Agar Gel; D004720:Endonucleases; D006037:Glyoxal; D009691:Nucleic Acid Denaturation; D009693:Nucleic Acid Hybridization; D011061:Poly A / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger; D012367:RNA, Viral / Q000378:metabolism*; D015719:Single-Strand Specific DNA and RNA Endonucleases; D014158:Transcription, Genetic
D004279:DNA, Viral; D012333:RNA, Messenger; D012367:RNA, Viral; D011061:Poly A; D006037:Glyoxal; D012313:RNA; D004720:Endonucleases; D015719:Single-Strand Specific DNA and RNA Endonucleases