Figure 2.

Morphology of budding and mature particles from various retroviruses. Electron micrographs of retroviral particles budding from infected cells (top panel) and of particles after the protease-mediated maturation (bottom panel). Abbreviations: MLV, murine leukemia virus; HTLV, human T cell leukemia virus ; HIV, human immunodeficiency virus; FV, foamy virus. Note that FV capsid assembly occurs in the cytoplasm similar to B/D typre retroviruses.