       Document 0548
 DOCN  M9650548
 TI    Intracellular trafficking of the human immunodeficiency virus type 1 Rev
       protein: involvement of continued rRNA synthesis in nuclear retention.
 DT    9605
 AU    D'Agostino DM; Ciminale V; Pavlakis GN; Chieco-Bianchi L; Institute of
       Oncology, University of Padova, Italy.
 SO    AIDS Res Hum Retroviruses. 1995 Sep;11(9):1063-71. Unique Identifier :
       AIDSLINE MED/96089213
 AB    We have explored the mechanism directing the intracellular trafficking
       and nucleolar accumulation of the human immunodeficiency virus type 1
       (HIV-1) Rev protein. Treatment of Rev-expressing cells with mycophenolic
       acid, an inhibitor of inosine monophosphate dehydrogenase, resulted in a
       redistribution of Rev from the nucleoli to the nucleoplasm and
       cytoplasm. In contrast, a Rev effector domain mutant was retained in the
       nucleus, indicating the involvement of this domain in the protein's
       nuclear retention/nucleocytoplasmic transport. Identical results were
       obtained by inhibiting transcription using actinomycin D or
       5,6-dichlorobenzimidazole riboside. All three drugs were found to
       inhibit biosynthetic labeling of ribosomal RNA and to disrupt nucleolar
       morphology, suggesting a correlation between nucleolar/nuclear retention
       of Rev, continued ribosomal RNA synthesis, and intact nucleolar
       architecture. Results of binding/immunofluorescence assays using
       isolated, permeabilized nuclei and extracts of cells expressing Rev
       demonstrated that the protein is able to bind to nucleoli in vitro, in
       the absence of active cellular processes or eukaryotic posttranslational
       modifications. Rev derived from actinomycin D-treated cells showed
       equivalent binding, indicating that the inhibitor did not directly
       interfere with the ability of the protein to interact with nucleolar
       structures. Rev's interaction with nucleoli was directed by the
       protein's arginine-rich RNA-binding/nucleolar localization domain, and
       was abrogated by pretreatment of the nuclei with RNaseA, indicating a
       requirement for RNA, probably ribosomal RNA.
 DE    Cell Nucleolus/DRUG EFFECTS/METABOLISM/VIROLOGY  Cell Nucleus/DRUG
       EFFECTS/METABOLISM/VIROLOGY  Dactinomycin/PHARMACOLOGY
       Dichlororibofuranosylbenzimidazole/PHARMACOLOGY  Enzyme
       Inhibitors/PHARMACOLOGY  Gene Products, rev/GENETICS/*METABOLISM  Hela
       Cells  Human  HIV-1/GENETICS/*METABOLISM  IMP Dehydrogenase/ANTAGONISTS
       & INHIB  Mutation  Mycophenolic Acid/PHARMACOLOGY  Protein Synthesis
       Inhibitors/PHARMACOLOGY  RNA, Ribosomal/*BIOSYNTHESIS  RNA,
       Viral/*BIOSYNTHESIS  Support, Non-U.S. Gov't  Support, U.S. Gov't,
       P.H.S.  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

