Transport to nucleus
In a cell, structures in excess of 20nm require energy-dependent motility to travel through the cytosol. HBV capsids are about 35nm large and use an active transport along microtubules to reach the cell nucleus("Rabe et al. 2006":http://www.ncbi.nlm.nih.gov/pubmed/16699026) Rating=1 (Kann et al. 2007) Review. Hao et al. suggest an actine-mediated transport but their study is based on internalized HBsAg particle (Hao et al. 2011) Rating=1
All mammalian viruses that are targeted into the nucleus are using the microtubules. Therefore the interpretation of Rabe et al. of microtubule-dependent transport is much more convincing.