Adenoviral E2 IVa2 protein interacts with L4 33K protein and E2 DNA-binding protein.

Yadvinder S Ahi, Sai V Vemula, Suresh K Mittal

Department of Comparative Pathobiology, Purdue University Center for Cancer Research, and Bindley Bioscience Center, Purdue University, West Lafayette, IN, USA.

The Journal of general virology 2013 Jun

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Adenovirus (AdV) is thought to follow a sequential assembly pathway similar to that observed in dsDNA bacteriophages and herpesviruses. First, empty capsids are assembled, and then the genome is packaged through a ring-like structure, referred to as a portal, located at a unique vertex. In human AdV serotype 5 (HAdV5), the IVa2 protein initiates specific recognition of viral genome by associating with the viral packaging domain located between nucleotides 220 and 400 of the genome. IVa2 is located at a unique vertex on mature capsids and plays an essential role during genome packaging, most likely by acting as a DNA packaging ATPase. In this study, we demonstrated interactions among IVa2, 33K and DNA-binding protein (DBP) in virus-infected cells by in vivo cross-linking of HAdV5-infected cells followed by Western blot, and co-immunoprecipitation of IVa2, 33K and DBP from nuclear extracts of HAdV5-infected cells. Confocal microscopy demonstrated co-localization of IVa2, 33K and DBP in virus-infected cells and also in cells transfected with IVa2, 33K and DBP genes. Immunogold electron microscopy of purified HAdV5 showed the presence of IVa2, 33K or DBP at a single site on the virus particles. Our results provide indirect evidence that IVa2, 33K and DBP may form a complex at a unique vertex on viral capsids and cooperate in genome packaging.

Citation

Yadvinder S Ahi, Sai V Vemula, Suresh K Mittal. Adenoviral E2 IVa2 protein interacts with L4 33K protein and E2 DNA-binding protein. The Journal of general virology. 2013 Jun;94(Pt 6):1325-34