The adeno-associated virus type 5 small rep proteins expressed via internal translation initiation are functional.
Although precluded from using splicing to produce multiple small Rep proteins, adeno-associated virus type 5 (AAV5) generates a Rep40-like protein by alternative translation initiation at an internal AUG. A defined region upstream of the internal AUG was both required and sufficient to program internal initiation within AAV5 and may act similarly in heterologous contexts. The internally initiated AAV5 Rep40-like protein was functional and had helicase activity similar to that of AAV2 Rep40. Surprisingly, both the AAV5 Rep40-like protein and Rep52 were able to be translated from the AAV5 upstream P7-generated RNAs; however, the relative level of small to large Rep proteins was reduced compared to that of the wild type. A P19 mutant AAV5 infectious clone generated near-wild-type levels of the double-stranded monomer replicative form (mRF) replicative intermediate but reduced levels of virus, consistent with the previously defined role of Rep40-like proteins in genome encapsidation. Levels of mutant virus were dramatically reduced upon amplification.
Department of Molecular Microbiology and Immunology, School of Medicine Life Sciences Center, University of Missouri-Columbia, Columbia, Missouri, USA.
Olufemi
O
Fasina
David J
DJ
Pintel
D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D000229:Dependovirus / Q000201:enzymology* / Q000235:genetics; D015870:Gene Expression; D015967:Gene Expression Regulation, Viral; D014176:Protein Biosynthesis
D004265:DNA Helicases; C477740:Rep40 protein, adeno-associated virus