Adenovirus Chromatin: The Dynamic Nucleoprotein Complex Throughout Infection

Abstract

Adenovirus (Ad) is a widely studied DNA virus, but the nucleoprotein structure of the viral genome in the cell is poorly characterized. Our objective is to study Ad DNA-protein associations and how these affect the viral life cycle. Most of the viral DNA condensing protein, protein VII, is lost within a few hours of infection and this loss is independent of transcription. Cellular histones associate with the viral DNA after removal of protein VII, with a preferential deposition of H3.3. Micrococcal nuclease accessibility assays at 6 hpi showed laddering of the viral DNA, suggesting the genome is wrapped in physiologically spaced nucleosomes. Although viral DNA continues to associate with H3.3 at late times of infection, the overall level of association with histones is greatly reduced. Knockdown of the H3.3 chaperone HIRA had no effect on the viral life cycle suggesting that other H3.3 chaperones are involved. Our studies have begun to elucidate the nucleoprotein structure of Ad DNA in the infected cell nucleus.