Early events in the interaction of adenoviruses with HeLa cells: III. Relationship between an ATPase activity in nuclear envelopes and transfer of core material: a hypothesis

Abstract

Morphological evidence was obtained indicating that transfer of cores from inoculum particles into nuclei of HeLa cells occurs at the nuclear pore complex (NP). When nuclei are released by means of detergent from cells sampled 30 min after initiating penetration, only particles with dense cores are attached to NP. In material taken at later times, empty attached capsids are evident indicating that inoculum virus becomes complexed firmly with the NP where transfer may occur. Quasi-intact nuclear envelopes were isolated by a new procedure from uninfected HeLa cells. They contain an Mg 2+-requiring ATPase, which is optimally active at neutrality and has a Michaelis constant of 1.2 × 10 −4 M. Localization of the ATPase activity in isolated envelopes was carried out by means of electron microscopic cytochemistry. Presence of dense precipitates, presumed to represent the reaction product, was found in the vicinity of NP. A hypothesis currently favored by us postulates that an energetic process existing in the NP is involved with transfer of adenovirus cores and fulfills a more general role in nucleocytoplasmic movement of materials.