Nuclear Localization Signal(s) Required for Nuclear Targeting of the Maize Regulatory Protein Opaque-2

1992 ◽  
Vol 4 (10) ◽  
pp. 1213
Author(s):  
Marguerite J. Varagona ◽  
Robert J. Schmidt ◽  
Natasha V. Raikhel
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Regulatory Protein ◽  
Nuclear Targeting ◽  
Localization Signal

scholarly journals Coordinate Nuclear Targeting of the FANCD2 and FANCI Proteins via a FANCD2 Nuclear Localization Signal

PLoS ONE ◽  
2013 ◽  
Vol 8 (11) ◽  
pp. e81387 ◽  
Author(s):  
Rebecca A. Boisvert ◽  
Meghan A. Rego ◽  
Paul A. Azzinaro ◽  
Maurizio Mauro ◽  
Niall G. Howlett
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Nuclear Targeting ◽  
Localization Signal

Nuclear targeting of the cauliflower mosaic virus (CaMV) genomeThis review is one of a selection of papers published in the Special Issue on Plant Cell Biology.

2006 ◽  
Vol 84 (4) ◽  
pp. 565-571
Author(s):  
Julie Champagne ◽  
Denis Leclerc
Keyword(s):  
Mosaic Virus ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Cell Biology ◽  
Plant Viruses ◽  
Cauliflower Mosaic Virus ◽  
Nuclear Pore ◽  
Regulatory Sequences ◽  
Nuclear Targeting ◽  
Localization Signal

The delivery of the double-stranded DNA viral genome into the nucleus is a critical step for the type member of Caulimoviridae, cauliflower mosaic virus (CaMV). The nucleocapsid (NC) of CaMV is directly involved in this process. A nuclear localization signal located at the N-terminus of the NC was shown to be exposed at the surface of the virion. This nuclear localization signal appears to be important to direct the virus to the nuclear pore complex. The nuclear targeting of the NC needs to be tightly regulated because the process of virus assembly, which also involves the viral NC, occurs in the cytosol. It is now accepted that the N- and C-terminal extensions of the viral NC precursor are efficient regulatory sequences that determine the localization of the viral NC in infected leaves. Proteolytic maturation and phosphorylation of the N- and C-terminal extensions are also important in the regulation of this process. Despite these recent discoveries, the transport of CaMV toward and into the nucleus during early events in the infection cycle remains unclear. In this review, we summarize recent advances that explain the mechanisms of targeting of the CaMV genome to the nucleus and extract from other related animal and plant viruses mechanisms that could hint at the possible strategies used by CaMV to enter the nucleus.

scholarly journals The Novel Nuclear Targeting and BFRF1-Interacting Domains of BFLF2 Are Essential for Efficient Epstein-Barr Virus Virion Release

2019 ◽  
Vol 94 (3) ◽  
Author(s):  
Yu-Ching Dai ◽  
Yen-Tzu Liao ◽  
Yi-Ting Juan ◽  
Yi-Ying Cheng ◽  
Mei-Tzu Su ◽  
...  
Keyword(s):  
Amino Acids ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Epstein Barr Virus ◽  
The Novel ◽  
Nuclear Targeting ◽  
Barr Virus ◽  
Nuclear Egress ◽  
Localization Signal ◽  
Epstein Barr

ABSTRACT Epstein-Barr virus (EBV) genomic DNA is replicated and packaged into procapsids in the nucleus to form nucleocapsids, which are then transported into the cytoplasm for tegumentation and final maturation. The process is facilitated by the coordination of the viral nuclear egress complex (NEC), which consists of BFLF2 and BFRF1. By expression alone, BFLF2 is distributed mainly in the nucleus. However, it colocalizes with BFRF1 at the nuclear rim and in cytoplasmic nuclear envelope-derived vesicles in coexpressing cells, suggesting temporal control of the interaction between BFLF2 and BFRF1 is critical for their proper function. The N-terminal sequence of BFLF2 is less conserved than that of alpha- and betaherpesvirus homologs. Here, we found that BFLF2 amino acids (aa) 2 to 102 are required for both nuclear targeting and its interaction with BFRF1. Coimmunoprecipitation and confocal analysis indicated that aa 82 to 106 of BFLF2 are important for its interaction with BFRF1. Three crucial amino acids (R47, K50, and R52) and several noncontinuous arginine and histidine residues within aa 59 to 80 function together as a noncanonical nuclear localization signal (NLS), which can be transferred onto yellow fluorescent protein (YFP)-LacZ for nuclear targeting in an importin β-dependent manner. Virion secretion is defective in 293 cells harboring a BFLF2 knockout EBV bacmid upon lytic induction and is restored by trans-complementation of wild-type BFLF2, but not NLS or BFRF1-interacting defective mutants. In addition, multiple domains of BFRF1 were found to bind BFLF2, suggesting multiple contact regions within BFRF1 and BFLF2 are required for proper nuclear egress of EBV nucleocapsids. IMPORTANCE Although Epstein-Barr virus (EBV) BFRF1 and BFLF2 are homologs of conserved viral nuclear egress complex (NEC) in all human herpesviruses, unique amino acid sequences and functions were identified in both proteins. In this study, the nuclear targeting and BFRF1-interacting domains were found within the N terminus of BFLF2. We showed that amino acids (aa) 82 to 106 are the major region required for BFLF2 to interact with BFRF1. However, the coimmunoprecipitation (Co-IP) data and glutathione transferase (GST) pulldown experiments revealed that multiple regions of both proteins contribute to reciprocal interactions. Different from the canonical nuclear localization signal (NLS) in other herpes viral homologs, BFLF2 contains a novel importin-dependent nuclear localization signal, including R47, K50, and R52 and several neighboring discontinuous arginine and histidine residues. Using a bacmid complementation system, we show that both the nuclear targeting and the novel nuclear localization signal within aa 82 to 106 of BFLF2 are required for virion secretion.

scholarly journals HCF-1 Amino- and Carboxy-Terminal Subunit Association through Two Separate Sets of Interaction Modules: Involvement of Fibronectin Type 3 Repeats

2000 ◽  
Vol 20 (18) ◽  
pp. 6721-6730 ◽  
Author(s):  
Angus C. Wilson ◽  
Michael Boutros ◽  
Kristina M. Johnson ◽  
Winship Herr
Keyword(s):  
Nuclear Localization ◽  
Protein Interactions ◽  
Nuclear Localization Signal ◽  
Regulatory Protein ◽  
Proteolytic Processing ◽  
Structural Motif ◽  
Localization Signal ◽  
Carboxy Terminal ◽  
Type 3 ◽  
Fibronectin Type

ABSTRACT When herpes simplex virus infects permissive cells, the viral regulatory protein VP16 forms a specific complex with HCF-1, a preexisting nuclear protein involved in cell proliferation. The majority of HCF-1 in the cell is a complex of associated amino (HCF-1N)- and carboxy (HCF-1C)-terminal subunits that result from an unusual proteolytic processing of a large precursor polypeptide. Here, we have characterized the structure and function of sequences required for HCF-1N and HCF-1C subunit association. HCF-1 contains two matched pairs of self-association sequences called SAS1 and SAS2. One of these matched association sequences, SAS1, consists of a short 43-amino-acid region of the HCF-1N subunit, which associates with a carboxy-terminal region of the HCF-1Csubunit that is composed of a tandem pair of fibronectin type 3 repeats, a structural motif known to promote protein-protein interactions. Unexpectedly, the related protein HCF-2, which is not proteolyzed, also contains a functional SAS1 association element, suggesting that this element does not function solely to maintain HCF-1N and HCF-1C subunit association. HCF-1N subunits do not possess a nuclear localization signal. We show that, owing to a carboxy-terminal HCF-1 nuclear localization signal, HCF-1Csubunits can recruit HCF-1N subunits to the nucleus.

scholarly journals Human Cytomegalovirus UL84 Protein Contains Two Nuclear Export Signals and Shuttles between the Nucleus and the Cytoplasm

2006 ◽  
Vol 80 (20) ◽  
pp. 10274-10280 ◽  
Author(s):  
Peter Lischka ◽  
Claudia Rauh ◽  
Regina Mueller ◽  
Thomas Stamminger
Keyword(s):  
Human Cytomegalovirus ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Nuclear Export ◽  
Signal Sequence ◽  
Regulatory Protein ◽  
Nucleocytoplasmic Shuttling ◽  
Viral Dna ◽  
Nuclear Localization Signal Sequence ◽  
Localization Signal

ABSTRACT Previous studies defined pUL84 of human cytomegalovirus as an essential regulatory protein with nuclear localization that was proposed to act during initiation of viral-DNA synthesis. Recently, we demonstrated that a complex domain of 282 amino acids within pUL84 functions as a nonconventional nuclear localization signal. Sequence inspection of this domain revealed the presence of motifs with homology to leucine-rich nuclear export signals. Here, we report the identification of two functional, autonomous nuclear export signals and show that pUL84 acts as a CRM-1-dependent nucleocytoplasmic shuttling protein. This suggests an unexpected cytoplasmic role for this essential viral regulatory protein.

Sign in / Sign up

Export Citation Format

Share Document