scholarly journals Cytomegalovirus Assembly Protein Precursor and Proteinase Precursor Contain Two Nuclear Localization Signals That Mediate Their Own Nuclear Translocation and That of the Major Capsid Protein

1998 ◽  
Vol 72 (10) ◽  
pp. 7722-7732 ◽  
Author(s):  
Scott M. Plafker ◽  
Wade Gibson
Keyword(s):  
Capsid Protein ◽  
Nuclear Localization ◽  
Major Capsid Protein ◽  
Nuclear Translocation ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Protein Precursor ◽  
Nuclear Localization Signals ◽  
Carboxy Terminal

ABSTRACT The cytomegalovirus (CMV) assembly protein precursor (pAP) interacts with the major capsid protein (MCP), and this interaction is required for nuclear translocation of the MCP, which otherwise remains in the cytoplasm of transfected cells (L. J. Wood et al., J. Virol. 71:179–190, 1997). We have interpreted this finding to indicate that the CMV MCP lacks its own nuclear localization signal (NLS) and utilizes the pAP as an NLS-bearing escort into the nucleus. The CMV pAP amino acid sequence has two clusters of basic residues (e.g., KRRRER [NLS1] and KARKRLK [NLS2], for simian CMV) that resemble the simian virus 40 large-T-antigen NLS (D. Kalderon et al., Cell 39:499–509, 1984) and one of these (NLS1) has a counterpart in the pAP homologs of other herpesviruses. The work described here establishes that NLS1 and NLS2 are mutually independent NLS that can act (i) in cisto translocate pAP and the related proteinase precursor (pNP1) into the nucleus and (ii) in trans to transport MCP into the nucleus. By using combinations of NLS mutants and carboxy-terminal deletion constructs, we demonstrated a self-interaction of pAP and cytoplasmic interactions of pAP with pNP1 and of pNP1 with itself. The relevance of these findings to early steps in capsid assembly, the mechanism of MCP nuclear transport, and the possible cytoplasmic formation of protocapsomeric substructures is discussed.

scholarly journals A hydrophobic protein sequence can override a nuclear localization signal independently of protein context.

1991 ◽  
Vol 11 (10) ◽  
pp. 5137-5146 ◽  
Author(s):  
K van Zee ◽  
F Appel ◽  
E Fanning
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Heterologous Proteins ◽  
Wild Type ◽  
Terminal Sequence ◽  
Localization Signal ◽  
Carboxy Terminal

Simian virus 40 T antigen is specifically targeted to the nucleus by the signal Pro-Lys-Lys-128-Lys-Arg-Lys-Val. We have previously described the isolation of a simian virus 40 T-antigen mutant, 676FS, which retains a wild-type nuclear localization signal but fails to accumulate properly in the nucleus and interferes with the nuclear localization of heterologous proteins. Here we report that the hydrophobic carboxy-terminal sequence novel to 676FS T antigen overrides the nuclear localization signal if fused to other proteins, thereby anchoring the proteins in the cytoplasm. We discuss possible mechanisms by which missorting of such a fusion protein could interfere with the nuclear transport of heterologous proteins.

scholarly journals RanBP3 Contains an Unusual Nuclear Localization Signal That Is Imported Preferentially by Importin-α3

1999 ◽  
Vol 19 (12) ◽  
pp. 8400-8411 ◽  
Author(s):  
Katie Welch ◽  
Jacqueline Franke ◽  
Matthias Köhler ◽  
Ian G. Macara
Keyword(s):  
Nuclear Localization ◽  
Fluorescent Protein ◽  
Signal Sequence ◽  
Consensus Sequence ◽  
Full Range ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Nuclear Localization Signals ◽  
Importin Α

ABSTRACT The full range of sequences that constitute nuclear localization signals (NLSs) remains to be established. Even though the sequence of the classical NLS contains polybasic residues that are recognized by importin-α, this import receptor can also bind cargo that contains no recognizable signal, such as STAT1. The situation is further complicated by the existence of six mammalian importin-α family members. We report the identification of an unusual type of NLS in human Ran binding protein 3 (RanBP3) that binds preferentially to importin-α3. RanBP3 contains a variant Ran binding domain most similar to that found in the yeast protein Yrb2p. Anti-RanBP3 immunofluorescence is predominantly nuclear. Microinjection of glutathione S-transferase–green fluorescent protein–RanBP3 fusions demonstrated that a region at the N terminus is essential and sufficient for nuclear localization. Deletion analysis further mapped the signal sequence to residues 40 to 57. This signal resembles the NLSs of c-Myc and Pho4p. However, several residues essential for import via the c-Myc NLS are unnecessary in the RanBP3 NLS. RanBP3 NLS-mediated import was blocked by competitive inhibitors of importin-α or importin-β or by the absence of importin-α. Binding assays using recombinant importin-α1, -α3, -α4, -α5, and -α7 revealed a preferential interaction of the RanBP3 NLS with importin-α3 and -α4, in contrast to the simian virus 40 T-antigen NLS, which interacted to similar extents with all of the isoforms. Nuclear import of the RanBP3 NLS was most efficient in the presence of importin-α3. These results demonstrate that members of the importin-α family possess distinct preferences for certain NLS sequences and that the NLS consensus sequence is broader than was hitherto suspected.

scholarly journals A hydrophobic protein sequence can override a nuclear localization signal independently of protein context

1991 ◽  
Vol 11 (10) ◽  
pp. 5137-5146
Author(s):  
K van Zee ◽  
F Appel ◽  
E Fanning
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Heterologous Proteins ◽  
Wild Type ◽  
Terminal Sequence ◽  
Localization Signal ◽  
Carboxy Terminal

Simian virus 40 T antigen is specifically targeted to the nucleus by the signal Pro-Lys-Lys-128-Lys-Arg-Lys-Val. We have previously described the isolation of a simian virus 40 T-antigen mutant, 676FS, which retains a wild-type nuclear localization signal but fails to accumulate properly in the nucleus and interferes with the nuclear localization of heterologous proteins. Here we report that the hydrophobic carboxy-terminal sequence novel to 676FS T antigen overrides the nuclear localization signal if fused to other proteins, thereby anchoring the proteins in the cytoplasm. We discuss possible mechanisms by which missorting of such a fusion protein could interfere with the nuclear transport of heterologous proteins.

scholarly journals Analysis of a nuclear localization signal of simian virus 40 major capsid protein Vp1.

1996 ◽  
Vol 70 (2) ◽  
pp. 1317-1322 ◽  
Author(s):  
N Ishii ◽  
N Minami ◽  
E Y Chen ◽  
A L Medina ◽  
M M Chico ◽  
...  
Keyword(s):  
Capsid Protein ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Major Capsid Protein ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Localization Signal ◽  
Capsid Protein Vp1

scholarly journals Cell-Free Translation of Messenger RNA of Simian Virus 40: Synthesis of the Major Capsid Protein

1974 ◽  
Vol 71 (2) ◽  
pp. 302-306 ◽  
Author(s):  
C. L. Prives ◽  
H. Aviv ◽  
B. M. Paterson ◽  
B. E. Roberts ◽  
S. Rozenblatt ◽  
...  
Keyword(s):  
Capsid Protein ◽  
Messenger Rna ◽  
Major Capsid Protein ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Free Translation

scholarly journals Nuclear Transport of the Major Capsid Protein Is Essential for Adeno-Associated Virus Capsid Formation

1999 ◽  
Vol 73 (9) ◽  
pp. 7912-7915 ◽  
Author(s):  
Mainul Hoque ◽  
Ken-ichiro Ishizu ◽  
Akiko Matsumoto ◽  
Song-Iee Han ◽  
Fumio Arisaka ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Nuclear Transfer ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Capsid Proteins ◽  
Sufficient Information ◽  
Adeno Associated Virus ◽  
Functional Roles ◽  
Capsid Formation

ABSTRACT Adeno-associated virus capsids are composed of three proteins, VP1, VP2, and VP3. Although VP1 is necessary for viral infection, it is not essential for capsid formation. The other capsid proteins, VP2 and VP3, are sufficient for capsid formation, but the functional roles of each protein are still not well understood. By analyzing a series of deletion mutants of VP2, we identified a region necessary for nuclear transfer of VP2 and found that the efficiency of nuclear localization of the capsid proteins and the efficiency of virus-like particle (VLP) formation correlated well. To confirm the importance of the nuclear localization of the capsid proteins, we fused the nuclear localization signal of simian virus 40 large T antigen to VP3 protein. We show that this fusion protein could form VLP, indicating that the VP2-specific region located on the N-terminal side of the protein is not structurally required. This finding suggests that VP3 has sufficient information for VLP formation and that VP2 is necessary only for nuclear transfer of the capsid proteins.

scholarly journals The human DNA-activated protein kinase phosphorylates simian virus 40 T antigen at amino- and carboxy-terminal sites.

1991 ◽  
Vol 65 (10) ◽  
pp. 5131-5140 ◽  
Author(s):  
Y R Chen ◽  
S P Lees-Miller ◽  
P Tegtmeyer ◽  
C W Anderson
Keyword(s):  
Protein Kinase ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Human Dna ◽  
Carboxy Terminal

New Properties of Simian Virus 40 Large T Antigen

1982 ◽  
Vol 2 (12) ◽  
pp. 1463-1471
Author(s):  
Roland Seif
Keyword(s):  
Escherichia Coli ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Large T Antigen ◽  
Diisopropyl Fluorophosphate ◽  
Affinity Adsorbent ◽  
Human Papovavirus ◽  
Carboxy Terminal

An 8,000-molecular-weight (8K) T antigen was found in all cells transformed by simian virus 40. The 8K T antigen was weakly labeled in vivo with [ 35 S]methionine or 32 P i . A deletion in the human papovavirus BK genome, in the region coding for the carboxy-terminal end of the large T antigen, reduced the size of the 8K T antigen. The last 80 amino acids of the large T antigen include the sequence Asp-Asp-Asp-Asp unique to the activation peptide of trypsinogen. Large T antigen bound diisopropyl fluorophosphate and was retained by d -phenylalanine coupled to Sepharose beads, an affinity adsorbent that can retain chymotrypsin. The large T antigen and the recA protein of Escherichia coli , a known protease, have several properties in common as well as several similar sequences. Antibodies against large T antigen interacted with native recA protein.

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