Cytomegalovirus primary envelopment occurs at large infoldings of the inner nuclear membrane.
We have investigated the morphogenesis of human and murine cytomegalovirus by transmission electron microscopy after high-pressure freezing, freeze substitution, and plastic embedding. We observed large tubular infoldings of the inner nuclear membrane that were free of lamina and active in primary envelopment and subsequent transport of capsids to the nuclear periphery. Semiquantitative determinations of the enlarged inner nuclear membrane area and the location of the primary envelopment of nucleocapsids demonstrated that this structure represents a virus-induced specialized membrane domain at which the particles are preferentially enveloped. This is a previously undescribed structural element relevant in cytomegalovirus morphogenesis.
Buser
Christopher
C
Universitätsklinikum Ulm, Institut für Virologie, Albert Einstein Allee 11, 89081 Ulm, Germany.
Walther
Paul
P
Mertens
Thomas
T
Michel
Detlef
D
D000818:Animals; D002213:Capsid / Q000378:metabolism / Q000648:ultrastructure; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism / Q000648:ultrastructure / Q000821:virology; D002478:Cells, Cultured; D003587:Cytomegalovirus / Q000502:physiology* / Q000648:ultrastructure; D003586:Cytomegalovirus Infections / Q000473:pathology / Q000821:virology; D005347:Fibroblasts / Q000648:ultrastructure / Q000821:virology; D006566:Herpesviridae Infections / Q000473:pathology / Q000821:virology; D006801:Humans; D008297:Male; D051379:Mice; D008954:Models, Biological; D018146:Muromegalovirus / Q000502:physiology* / Q000648:ultrastructure; D009685:Nuclear Envelope / Q000378:metabolism* / Q000648:ultrastructure / Q000821:virology*; D012867:Skin / Q000166:cytology; D013997:Time Factors