scholarly journals The Membrane-Anchoring Region of the AcMNPV P74 Protein Is Expendable or Interchangeable with Homologs from Other Species

Viruses ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2416
Author(s):  
María Victoria Nugnes ◽  
Alexandra Marisa Targovnik ◽  
Adrià Mengual-Martí ◽  
María Victoria Miranda ◽  
Carolina Susana Cerrudo ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Virus Infectivity ◽  
Amino Terminal ◽  
Insect Pathogens ◽  
Transmembrane Regions ◽  
Membrane Anchoring ◽  
P74 Gene ◽  
Export Signal

Baculoviruses are insect pathogens that are characterized by assembling the viral dsDNA into two different enveloped virions during an infective cycle: occluded virions (ODVs; immersed in a protein matrix known as occlusion body) and budded virions (BVs). ODVs are responsible for the primary infection in midgut cells of susceptible larvae thanks to the per os infectivity factor (PIF) complex, composed of at least nine essential viral proteins. Among them, P74 is a crucial factor whose activity has been identified as virus-specific. In this work, the p74 gene from AcMNPV was pseudogenized using CRISPR/Cas9 technology and then complemented with wild-type alleles from SeMNPV and HearSNPV species, as well as chimeras combining the P74 amino and carboxyl domains. The results on Spodoptera exigua and Rachiplusia nu larvae showed that an amino terminal sector of P74 (lacking two potential transmembrane regions but possessing a putative nuclear export signal) is sufficient to restore the virus infectivity whether alone or fused to the P74 transmembrane regions of the other evaluated viral species. These results provide novel information about the functional role of P74 and delimit the region on which mutagenesis could be applied to enhance viral activity and, thus, produce better biopesticides.

scholarly journals NOVEL NPM1 EXON 5 MUTATIONS AND GENE FUSIONS LEADING TO ABERRANT CYTOPLASMIC NUCLEOPHOSMIN IN AML

Blood ◽  
2021 ◽  
Author(s):  
Maria Paola Martelli ◽  
Roberta Rossi ◽  
Alessandra Venanzi ◽  
Manja Meggendorfer ◽  
Vincenzo Maria Perriello ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Myeloid Leukemia ◽  
Nuclear Export Signal ◽  
Fusion Partner ◽  
Functional Studies ◽  
Exon 9 ◽  
Cytoplasmic Accumulation ◽  
Exon 11 ◽  
Export Signal

Nucleophosmin (NPM1) mutations in acute myeloid leukemia (AML) affect exon 12, but sporadically also exon 9 and 11, all causing changes at protein C-terminal end (loss of tryptophans and creation of a nuclear export signal-NES motif) that lead to aberrant cytoplasmic NPM1 (NPM1c+), detectable by immunohistochemistry. Combining immunohistochemistry and molecular analyses in 929 AML patients, we found non-exon 12 NPM1 mutations in 5/387 (1.3%) NPM1c+ cases. Besides mutations in exon 9 (n=1) and exon 11 (n=1), novel mutations in exon 5 were discovered (n=3). One more exon 5 mutation was identified in additional 141 AML patients selected for wild-type NPM1 exon 12. Furthermore, 3 NPM1 rearrangements (i.e. NPM1/RPP30, NPM1/SETBP1, NPM1/CCDC28A) were detected and characterized among 13,979 AML samples screened by cytogenetic/FISH and RNA sequencing. Functional studies demonstrated that in AML cases the new NPM1 proteins harboured an efficient extra NES, either newly created or already present in the fusion partner, ensuring its cytoplasmic accumulation. Our findings support NPM1 cytoplasmic relocation as critical for leukemogenesis and reinforce the role of immunohistochemistry in predicting any AML-associated NPM1 genetic lesions. Also, this study highlights the need for developing new specific assays for molecular diagnosis and monitoring of NPM1-mutated AML.

The nuclear export signal (NES) found in the amino-terminal region of carp MEK1 and MKK6 is lacking in carp MKK4

2002 ◽  
Vol 1575 (1-3) ◽  
pp. 139-142
Author(s):  
Hisashi Hashimoto ◽  
Yoshiyuki Matsuo ◽  
Yoshihiro Yokoyama ◽  
Haruhiko Toyohara ◽  
Morihiko Sakaguchi
Keyword(s):  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Terminal Region ◽  
Amino Terminal ◽  
Export Signal

scholarly journals Phosphorylation in the accessory domain of yeast histone chaperone protein 1 exposes the nuclear export signal sequence

2021 ◽  
Author(s):  
Sho Ashida ◽  
Rikuri Morita ◽  
Yasuteru Shigeta ◽  
Ryuhei Harada
Keyword(s):  
Cell Nucleus ◽  
Nuclear Export ◽  
Signal Sequence ◽  
Nuclear Export Signal ◽  
Md Simulations ◽  
Histone Chaperone ◽  
Chaperone Protein ◽  
Accessory Domain ◽  
Export Signal

Histone is a scaffold protein that constitutes nucleosomes with DNA in the cell nucleus. When forming histone, hetero octamer is assisted by histone chaperone proteins. As a histone chaperone protein, the crystal structure of yeast nucleosome assembly protein (yNap1) has been determined. For yNap1, a nuclear export signal/sequence (NES) has been identified as a part of the long -helix. Experimental evidence via mutagenesis on budding yeast suggests the NES is necessary for transport out from the cell nucleus. However, the NES is masked by a region defined as an accessory domain (AD). In addition, the role of the AD in nuclear transport has not been elucidated yet. To address the role of the AD, we focused on phosphorylation in the AD because proteome experiments have identified multiple phosphorylation sites of yNap1. To computationally treat phosphorylation, we performed all-atom molecular dynamics (MD) simulations for a set of non-phosphorylated and phosphorylated yNap1 (Nap1-nonP and Nap1-P). As an analysis, we addressed how the NES is exposed to the protein surface by measuring its solvent-access surface area (SASA). As a result, there was a difference in the SASA distributions between both systems. Quantitatively, the median of the SASA distribution of Nap1-P was greater than that of Nap1-nonP, meaning that phosphorylation in the AD exposed to the NES, resulting in increasing its accessibility. In conclusion, yNap1 might modulate the accessibility of the NES by dislocating the AD through phosphorylation.

scholarly journals Adenovirus Late Gene Expression Does Not Require a Rev-Like Nuclear RNA Export Pathway

2000 ◽  
Vol 74 (14) ◽  
pp. 6684-6688 ◽  
Author(s):  
Claudia Rabino ◽  
Anders Aspegren ◽  
Kara Corbin-Lickfett ◽  
Eileen Bridge
Keyword(s):  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Late Gene Expression ◽  
Export Pathway ◽  
Early Proteins ◽  
Immunodeficiency Virus ◽  
Rna Export ◽  
Nuclear Rna Export ◽  
Export Signal

ABSTRACT Adenovirus late mRNA export is facilitated by viral early proteins of 55 and 34 kDa. The 34-kDa protein contains a leucine-rich nuclear export signal (NES) similar to that of the human immunodeficiency virus Rev protein. It was proposed that the 34-kDa protein might facilitate the export of adenovirus late mRNA through a Rev-like NES-mediated export pathway. We have tested the role of NES-mediated RNA export during adenovirus infection, and we find that it is not essential for the expression of adenovirus late genes.

scholarly journals Characterization of the Interaction between the Interferon-Induced Protein P56 and the Int6 Protein Encoded by a Locus of Insertion of the Mouse Mammary Tumor Virus

2000 ◽  
Vol 74 (4) ◽  
pp. 1892-1899 ◽  
Author(s):  
Jinjiao Guo ◽  
Ganes C. Sen
Keyword(s):  
Nuclear Export ◽  
Nuclear Protein ◽  
Nuclear Export Signal ◽  
Structural Basis ◽  
Specific Domain ◽  
Interacting Protein ◽  
Amino Terminal ◽  
Tumor Virus ◽  
Export Signal ◽  
Two Hybrid

ABSTRACT For determining cellular functions of the interferon-inducible human cytoplasmic protein P56, we undertook a Saccharomyces cerevisiae two-hybrid screen that identified Int6 as a P56-interacting protein. That the interaction also occurs in human cells was confirmed by coimmunoprecipitation and the observed cytoplasmic displacement of nuclear Int6 upon coexpression of P56. Because Int6 has been claimed to be both a cytoplasmic and a nuclear protein, we investigated the structural basis of this discrepancy. By mutational analyses, we showed that the Int6 protein contains a bipartite nuclear localization signal and a nuclear export signal at the far end of the amino terminus. The 20 amino-terminal residues of Int6, when they were attached to a different nuclear protein, were sufficient to translocate that protein to the cytoplasm. Within this region, replacement of any of the three leucine residues with alanine destroyed the function of the export signal. The specific domain of P56 that is required for its interaction with Int6 was mapped using the yeast two-hybrid assay and a mammalian coimmunoprecipitation assay. Both assays demonstrated that the C-terminal region of P56 containing three specific tetratricopeptide motifs is required for this interaction. In contrast, removal of an internal domain of P56 enhanced the interaction, as quantified by the two-hybrid assay.

The Nup98-HoxA9 Leukemogenic Fusion Protein Blocks Xpo1 and Tap-Mediated Nuclear Export

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 5228-5228
Author(s):  
Yildirim Dogan ◽  
Sutapa Sahay ◽  
David C Dorn ◽  
Anna Franceschino ◽  
Michael Xu ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Conflicts Of Interest ◽  
Blast Crisis ◽  
Nuclear Export Signal ◽  
Nucleocytoplasmic Shuttling ◽  
Nuclear Trafficking ◽  
Myeloid Leukemias ◽  
Nuclear Export Receptor ◽  
Export Signal

Abstract Abstract 5228 In leukemia Nup98 fusion genes are found as a product of the reciprocal translocation between Nucleoporin 98 (nup98) and homeobox-cluster genes. Nup98-HoxA9 (NHA9), the product of the t(7;11) translocation, is detected in acute myeloid leukemias (AMLs) and as a secondary abnormality in blast crisis of chronic myeloid leukemia (CML). The role of NHA9 in leukemogenesis is complex and incompletely understood. Here, we show an abrogation of nucleocytoplasmic shuttling of the nuclear export receptor Xpo1 and Tap in NHA9-expressing cells by using retroviral nuclear trafficking as a model. Lentiviral Rev, the prototype for nuclear export signal (NES)-containing proteins is shuttled through the nucleopore by Xpo1. NHA9 sequestered Xpo1 from the nuclear rim into nuclear aggregates resulting in deficient Xpo1-dependent nuclear exit of Rev and its mRNA substrates. Tap is involved in mRNA nucleocytoplasmic shuttling and is also responsible for the nuclear export of D-type retrovirus CTE-mRNAs. By using Tap/CTE-mRNA nuclear export as a model we also found that Tap colocalized in NHA9 nuclear aggregates leading to impaired Tap-mediated nuclear exit of CTE-mRNA substrates. Leukemogenicity of Nup98 fusion proteins may be accounted for in part by defects in Tap and Xpo1-mediated export of their substrates. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The Adenovirus Type 5 E1B-55K Oncoprotein Actively Shuttles in Virus-Infected Cells, Whereas Transport of E4orf6 Is Mediated by a CRM1-Independent Mechanism

2001 ◽  
Vol 75 (12) ◽  
pp. 5677-5683 ◽  
Author(s):  
Tanja Dosch ◽  
Florian Horn ◽  
Grit Schneider ◽  
Friedrich Krätzer ◽  
Thomas Dobner ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Mrna Export ◽  
Nuclear Export Signal ◽  
Adenovirus Type ◽  
Alternative Mechanism ◽  
Leptomycin B ◽  
Infected Cells ◽  
Adenovirus Type 5 ◽  
Export Signal

ABSTRACT The E1B-55K and E4orf6 proteins of adenovirus type 5 are involved in viral mRNA export. Here we demonstrate that adenovirus infection does not inhibit the function of the E1B-55K nuclear export signal and that E1B-55K also shuttles in infected cells. Even during virus infection, E1B-55K was exported by the leptomycin B-sensitive CRM1 pathway, whereas E4orf6 transport appeared to be mediated by an alternative mechanism. Our results strengthen the potential role of E1B-55K as the “driving force” for adenoviral late mRNA export.

scholarly journals Generation of Influenza A Virus NS2 (NEP) Mutants with an Altered Nuclear Export Signal Sequence

2004 ◽  
Vol 78 (18) ◽  
pp. 10149-10155 ◽  
Author(s):  
Kiyoko Iwatsuki-Horimoto ◽  
Taisuke Horimoto ◽  
Yutaka Fujii ◽  
Yoshihiro Kawaoka
Keyword(s):  
Influenza A Virus ◽  
Nuclear Export ◽  
Influenza A ◽  
Signal Sequence ◽  
Nuclear Export Signal ◽  
Wild Type Virus ◽  
Wild Type ◽  
Amino Terminal ◽  
Ribonucleoprotein Complexes ◽  
Export Signal

ABSTRACT The NS2 (NEP) protein of influenza A virus contains a highly conserved nuclear export signal (NES) motif in its amino-terminal region (12ILMRMSKMQL21, A/WSN/33), which is thought to be required for nuclear export of viral ribonucleoprotein complexes (vRNPs) mediated by a cellular export factor, CRM1. However, simultaneous replacement of three hydrophobic residues in the NES with alanine does not affect NS2 (NEP) binding to CRM1, although the virus with these mutations is not viable. To determine the extent of sequence conservation required by the NS2 (NEP) NES for its export function during viral replication, we randomly introduced mutations by degenerative mutagenesis into the region of NS cDNA encoding the NS2 (NEP) NES and then attempted to generate mutant viruses containing these alterations by reverse genetics. Sequence analysis of the recovered viruses showed that although some of the mutants possessed amino acids other than those conserved in the NES, hydrophobicity within this motif was maintained. Nuclear export of vRNPs representing all of the mutant viruses was completely inhibited in the presence of a CRM1 inhibitor, leptomycin B, as was the transport of wild-type virus, indicating that the CRM1-mediated pathway is responsible for the nuclear export of both wild-type and mutant vRNPs. The vRNPs of some of the mutant viruses were exported in a delayed manner, resulting in limited viral growth in cell culture and in mice. These results suggest that the NES motif may be an attractive target for the introduction of attenuating mutations in the production of live vaccine viruses.

Sign in / Sign up

Export Citation Format

Share Document