Adeno-Associated Virus Rep Protein-Mediated Inhibition of Transcription of the Adenovirus Major Late Promoter In Vitro

摘要: Adeno-associated virus (AAV) is a human parvovirus that normally requires helper such as adenovirus (Ad) for replication. The four AAV replication proteins (Rep78, Rep68, Rep52, and Rep40) are pleiotropic effectors of integration, replication, transcription, virion assembly. These exert effects on Ad gene expression In transient plasmid transfection assays, Rep inhibit from variety transcription promoters. We have examined protein-mediated inhibition the major late promoter (AdMLP) in vitro. Rep78/68 strongest suppressors purine nucleotide binding site proteins, by implication, ATPase activity or conformational change induced required full repression. Rep52 has modest effects, Rep40 exerts no significant effect transcription. their N-terminal 225-residue domain bind to 55-bp AdMLP DNA fragment gel shift suggesting protein-DNA interactions inhibition. This interaction was confirmed DNase I protection assays maps region extending TATA box initiation site. Gel shift, I, chemical cross-linking with box-binding protein (TBP) Rep68 indicate both interact each other at adjacent sites. demonstration TBP suggests alter preinitiation complex RNA polymerase II observations provide new insight into mechanism Rep-mediated expression.