Cytoskeletal proteins associated with intracytoplasmic human adenovirus at an early stage of infection

Taking advantage of the sedimentation properties of adenovirus particles, adenovirus-infected baby hamster kidney (BHK21) cells were reversibly fixed with cleavable diimidoester dimethyl 3,3′-dithiobispropionimidate (DTBP) at early times of infection (30 min). Cytoskeletal proteins associated with/or in close vicinity to virions were isolated as a complex cross-linked with carrier virus. Four major cellular proteins were thus found to co-purify with adenovirus particles. They were characterized by their coordinates on 2D maps and immunological reactivity. Two of them were identified as alpha-tubulin (58 kD), and vimentin subunits (56 kD). The two other species 68 and 66 kD might correspond to stress proteins. Affinity blotting on gels showed that both alpha-tubulin and vimentin were capable of binding with intact and penton-less adenovirions. Adenovirus components involved in the binding seemed to be mainly core proteins V and VII, and to a lesser extent, hexon. Analysis of neighbor relationships among proteins of the adenovirus-cytoskeletal protein cross-linked complex suggested that some capsid alterations occurred upon/or after entry of the virus into the cell, and that these structural modifications preferentially concerned the vertex components penton and IIIa, and the core protein V.