The activation domain of a hormone inducible HTLV-1 Rex protein determines colocalization with the nuclear pore

S. Rehberger, F. Gounari, M. Ducdodon, K. Chlichlia, L. Gazzolo, V. Schirrmacher, Khashayarsha Khazaie

Research output: Contribution to journalArticle

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Abstract

Human T-cell leukemia/lymphoma virus type 1 (HTLV-1) Rex is an essential regulatory protein that acts at the posttranscriptional level to promote expression of unspliced and singly spliced genes of the virus. Rex functions have been attributed to at least three separate domains of the protein determining nuclear/nucleolar accumulation and RNA binding (overlapping), multimerization, and nuclear export of Rex-responsive RNA. The steady-state intracellular localization of functional Rex molecules is mainly nucleolar. Fusions of wild-type Rex and the ligand binding domain of human estrogen receptor (ER) produced conditional molecules (ERRex and ERalaRex), which remained cytoplasmic in the absence of hormone and in response to hormone colocalized with the nuclear pore complex (NPC). These molecules induced in a hormone-dependent manner the expression of a Rex reporter plasmid and of the HTLV-1 Env protein and fusion of Env expressing cells. In contrast, activation domain mutants (ERRexΔ and ERRexGly) translocated from the cytoplasm and acquired a diffuse nuclear localization. These mutants did not associate with the NPC and failed to show any of the expected Rex functions. Rex functions were perturbed by inactivating the RNA binding domain (mutant ERM2) or the oligomerization domain (mutant ERM7). However, these two mutant fusion proteins exhibited a hormone-dependent NPC colocalization. These observations provide in vivo evidence that intranuclear translocation of intact Rex to the NPC is dependent exclusively on a functional activation domain and is not influenced by binding to the target RNA.

Original languageEnglish (US)
Pages (from-to)363-371
Number of pages9
JournalExperimental Cell Research
Volume233
Issue number2
DOIs
StatePublished - Jun 15 1997
Externally publishedYes

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rex Gene Products
Deltaretrovirus
Nuclear Pore
Hormones
RNA
env Gene Products
Cell Nucleus Active Transport
Recombinant DNA
Mutant Proteins
Nuclear Proteins
Estrogen Receptors
Cytoplasm
Plasmids
Ligands
Viruses
Proteins

ASJC Scopus subject areas

  • Cell Biology

Cite this

The activation domain of a hormone inducible HTLV-1 Rex protein determines colocalization with the nuclear pore. / Rehberger, S.; Gounari, F.; Ducdodon, M.; Chlichlia, K.; Gazzolo, L.; Schirrmacher, V.; Khazaie, Khashayarsha.

In: Experimental Cell Research, Vol. 233, No. 2, 15.06.1997, p. 363-371.

Research output: Contribution to journalArticle

Rehberger, S. ; Gounari, F. ; Ducdodon, M. ; Chlichlia, K. ; Gazzolo, L. ; Schirrmacher, V. ; Khazaie, Khashayarsha. / The activation domain of a hormone inducible HTLV-1 Rex protein determines colocalization with the nuclear pore. In: Experimental Cell Research. 1997 ; Vol. 233, No. 2. pp. 363-371.
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