Amino-terminal polypeptides of vimentin are responsible for the changes in nuclear architecture associated with human immunodeficiency virus type 1 protease activity in tissue culture cells.
Electron microscopy of human skin fibroblasts syringe-loaded with human immunodeficiency virus type 1 protease (HIV-1 PR) revealed several effects on nuclear architecture. The most dramatic is a change from a spherical nuclear morphology to one with multiple lobes or deep invaginations. The nuclear matrix collapses or remains only as a peripheral rudiment, with individual elements thicker than in control cells. Chromatin organization and distribution is also perturbed. Attempts to identify a major nuclear protein whose cleavage by the protease might be responsible for these alterations were unsuccessful. Similar changes were observed in SW 13 T3 M [vimentin(+)] cells, whereas no changes were observed in SW 13 [vimentin(-)] cells after microinjection of protease. Treatment of SW 13 [vimentin(-)] cells, preinjected with vimentin to establish an intermediate filament network, with HIV-1 PR resulted in alterations in chromatin staining and distribution, but not in nuclear shape. These same changes were produced in SW 13 [vimentin(-)] cells after the injection of a mixture of vimentin peptides, produced by the cleavage of vimentin to completion by HIV-1 PR in vitro. Similar experiments with 16 purified peptides derived from wild-type or mutant vimentin proteins and five synthetic peptides demonstrated that exclusively N-terminal peptides were capable of altering chromatin distribution. Furthermore, two separate regions of the N-terminal head domain are primarily responsible for perturbing nuclear architecture. The ability of HIV-1 to affect nuclear organization via the liberation of vimentin peptides may play an important role in HIV-1-associated cytopathogenesis and carcinogenesis.
Shoeman
R L
RL
Max-Planck-Institut für Zellbiologie, Rosenhof, D-68526 Ladenburg, Germany. rshoeman@zellbio.mpg.de
Hüttermann
C
C
Hartig
R
R
Traub
P
P
D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects* / Q000473:pathology / Q000648:ultrastructure; D002478:Cells, Cultured / Q000187:drug effects / Q000648:ultrastructure / Q000821:virology*; D002843:Chromatin / Q000187:drug effects / Q000648:ultrastructure; D046508:Culture Techniques; D016333:HIV Protease / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D051379:Mice; D008845:Microinjections; D018613:Microscopy, Confocal; D010455:Peptides / Q000138:chemical synthesis / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D014746:Vimentin / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*
D002843:Chromatin; D010455:Peptides; D014746:Vimentin; D016333:HIV Protease