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A novel transferable nuclear export signal mediates CRM1‐independent nucleocytoplasmic shuttling of the human cytomegalovirus transactivator protein pUL69
Author(s) -
Lischka Peter,
Rosorius Olaf,
Trommer Erik,
Stamminger Thomas
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.24.7271
Subject(s) - biology , transactivation , nuclear export signal , nuclear transport , microbiology and biotechnology , nuclear protein , cell nucleus , genetics , virology , nucleus , gene , gene expression , transcription factor
The best studied nuclear export processes are mediated by classical leucine‐rich nuclear export signals that specify recognition by the CRM1 export receptor. However, details concerning alternative nuclear export signals and pathways are beginning to emerge. Within the family of Herpesviridae, a set of homologous regulatory proteins that are exemplified by the ICP27 of herpes simplex virus were described recently as nucleocytoplasmic shuttling proteins. Here we report that pUL69 of the β‐herpesvirus human cytomegalovirus is a nuclear protein that is able to shuttle between the nucleus and the cytoplasm independently of virus‐encoded cofactors. In contrast to proteins containing a leucine‐rich export signal, the shuttling activity of pUL69 was not affected by leptomycin B, indicating that pUL69 trafficking is not mediated by the export receptor CRM1. Importantly, we identified and characterized a novel type of transferable, leptomycin B‐insensitive export signal that is distinct from other export signals described previously and is required for pUL69‐mediated activation of gene expression. These data suggest that pUL69 is exported via a novel nuclear export pathway, based on a so far unique nuclear export signal of 28 amino acids.