Vpr makes holes

The Vpr protein from HIV-1 makes holes in the nucleus, according to Warner Greene (Gladstone Institute of Virology and Immunology, University of California, San Francisco, CA) and colleagues. The holes allow the mixing of proteins that are usually exclusively nuclear or cytoplasmic. The damage, the mixing, or both may cause a G2 cell cycle arrest that allows the virus to replicate more efficiently.

For some time Greene has been studying the ability of Vpr to arrest the cell cycle. Vpr shuttles into the nucleus, so Greene suspected that it could affect the shuttling of other proteins. But protein-localization studies on populations of infected cells yielded inconsistent, fluctuating results that could not be reproduced. So Greene suggested single cell studies, the results of which are presented by de...