Xenopus nuclear factor 7 (xnf7) possesses an NLS that functions efficiently in both oocytes and embryos

1993 ◽  
Vol 105 (2) ◽  
pp. 389-395
Author(s):  
X. Li ◽  
L.D. Etkin
Keyword(s):  
Transcription Factor ◽  
Zinc Finger ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Nuclear Accumulation ◽  
Nuclear Factor ◽  
Zinc Finger Gene ◽  
Early Embryos ◽  
Localization Signal ◽  
Nuclear Phosphoprotein

Xenopus nuclear factor 7 (xnf7) is a nuclear phosphoprotein that is encoded by a member of a novel zinc finger gene family and likely functions as a transcription factor. It possesses a nuclear localization signal (NLS) similar to the bipartite basic NLS of nucleoplasmin, but unlike nucleoplasmin, which re-enters nuclei immediately after fertilization, xnf7 remains cytoplasmic until the mid-blastula transition (MBT). We have measured the accumulation of injected labeled xnf7 protein or protein produced from synthetic xnf7 transcripts in the oocyte nuclei (GV). The data show that the NLS of xnf7 functions efficiently in oocytes. Mutations in either of the bipartite basic domains of the xnf7 NLS inhibit nuclear accumulation, while mutations in the spacer sequences have no effect. The xnf7 NLS linked to pyruvate kinase directs the efficient accumulation of this protein into nuclei of early embryos prior to the MBT. These data suggest that retention of the xnf7 protein during development is the result of a mechanism that interferes with the xnf7 NLS function.

Nuclear accumulation of the E2F heterodimer regulated by subunit composition and alternative splicing of a nuclear localization signal

1996 ◽  
Vol 109 (10) ◽  
pp. 2443-2452 ◽  
Author(s):  
S. de la Luna ◽  
M.J. Burden ◽  
C.W. Lee ◽  
N.B. La Thangue
Keyword(s):  
Cell Cycle ◽  
Transcription Factor ◽  
Alternative Splicing ◽  
Dna Binding ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Binding Activity ◽  
Nuclear Accumulation ◽  
Dna Binding Activity ◽  
Localization Signal

The cellular transcription factor E2F plays a critical role in integrating cell cycle progression with the transcription apparatus by virtue of a physical interaction and control by key regulators of the cell cycle, such as pRb, cyclins and cyclin-dependent kinases. Generic E2F DNA binding activity arises when a member of two families of proteins, E2F and DP, form heterodimeric complexes, an interaction which results in co-operative transcriptional and DNA binding activity. Here, we characterise a new and hitherto unexpected mechanism of control influencing the activity of E2F which is mediated at the level of intracellular location through a dependence on heterodimer formation for nuclear translocation. Nuclear accumulation is dramatically influenced by two distinct processes: alternative splicing of a nuclear localization signal and subunit composition of the E2F heterodimer. These data define a new level of control in the E2F transcription factor whereby interplay between subunits dictates the levels of nuclear DNA binding activity.

Identification of a nuclear localization signal, RRMKWKK, in the homeodomain transcription factor PDX-1

FEBS Letters ◽  
1999 ◽  
Vol 461 (3) ◽  
pp. 229-234 ◽  
Author(s):  
Tilo Moede ◽  
Barbara Leibiger ◽  
Hamedeh Ghanaat Pour ◽  
Per-Olof Berggren ◽  
Ingo B Leibiger
Keyword(s):  
Transcription Factor ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Homeodomain Transcription Factor ◽  
Localization Signal

scholarly journals Ebolavirus VP24 Binding to Karyopherins Is Required for Inhibition of Interferon Signaling

2009 ◽  
Vol 84 (2) ◽  
pp. 1169-1175 ◽  
Author(s):  
Mathieu Mateo ◽  
St. Patrick Reid ◽  
Lawrence W. Leung ◽  
Christopher F. Basler ◽  
Viktor E. Volchkov
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Nuclear Accumulation ◽  
Interferon Signaling ◽  
Loss Of Function ◽  
Proposed Model ◽  
Localization Signal ◽  
Ifn Γ ◽  
Alpha Beta ◽  
Signal Receptors

ABSTRACT The Ebolavirus VP24 protein counteracts alpha/beta interferon (IFN-α/β) and IFN-γ signaling by blocking the nuclear accumulation of tyrosine-phosphorylated STAT1 (PY-STAT1). According to the proposed model, VP24 binding to members of the NPI-1 subfamily of karyopherin alpha (KPNα) nuclear localization signal receptors prevents their binding to PY-STAT1, thereby preventing PY-STAT1 nuclear accumulation. This study now identifies two domains of VP24 required for inhibition of IFN-β-induced gene expression and PY-STAT1 nuclear accumulation. We demonstrate that loss of function correlates with loss of binding to KPNα proteins. Thus, the VP24 IFN antagonist function requires the ability of VP24 to interact with KPNα.

scholarly journals A constitutive nuclear localization signal from the second zinc-finger of orphan nuclear receptor TR2

1998 ◽  
Vol 159 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Z Yu ◽  
CH Lee ◽  
C Chinpaisal ◽  
LN Wei
Keyword(s):  
Nuclear Receptor ◽  
Zinc Finger ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Fluorescent Protein ◽  
Biologically Active ◽  
Binding Property ◽  
Orphan Nuclear Receptor ◽  
Mobility Shift ◽  
Localization Signal

The orphan nuclear receptor TR2 and its truncated isoform deleted in the ligand binding domain (LBD) were localized exclusively in the nuclei as revealed by two methods of detection. An anti-hemagglutinin (HA) antibody detected specific nuclear localization of HA-tagged receptors and the green fluorescent protein (GFP)-tagged receptors were found to be distributed in the nuclei of living cells. By deletion analyses, the sequence responsible for targeting this receptor into the nucleus was defined. A stretch of 20 amino acid residues (KDCVINKHHRNRCQYCRLQR) within the second zinc-finger of this receptor is required for its nuclear localization and this signal is constitutively active. No nuclear localization signal was found in the N-terminus or the LBD. The GFP-tagged receptor remained biologically active, as evidenced by its repressive activity on the reporter that carried a binding site for this receptor, a direct repeat-5 (DR5). An electrophoretic mobility shift assay was performed to characterize the binding property of TR2 and its truncated isoform. TR2 bound to the DR5 as dimers whereas its truncated isoform bound as monomers.

scholarly journals Mechanisms Directing the Nuclear Localization of the CtBP Family Proteins

2006 ◽  
Vol 26 (13) ◽  
pp. 4882-4894 ◽  
Author(s):  
Alexis Verger ◽  
Kate G. R. Quinlan ◽  
Linda A. Crofts ◽  
Stefania Spanò ◽  
Daniela Corda ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Nuclear Import ◽  
Nuclear Localization Signal ◽  
Transcriptional Repression ◽  
Intracellular Trafficking ◽  
Nuclear Accumulation ◽  
Splice Isoforms ◽  
Localization Signal ◽  
Splice Isoform ◽  
Partner Proteins

ABSTRACT The C-terminal binding protein (CtBP) family includes four proteins (CtBP1 [CtBP1-L], CtBP3/BARS [CtBP1-S], CtBP2, and RIBEYE) which are implicated both in transcriptional repression and in intracellular trafficking. However, the precise mechanisms by which different CtBP proteins are targeted to different subcellular regions remains unknown. Here, we report that the nuclear import of the various CtBP proteins and splice isoforms is differentially regulated. We show that CtBP2 contains a unique nuclear localization signal (NLS) located within its N-terminal region, which contributes to its nuclear accumulation. Using heterokaryon assays, we show that CtBP2 is capable of shuttling between the nucleus and cytoplasm of the cell. Moreover, CtBP2 can heterodimerize with CtBP1-L and CtBP1-S and direct them to the nucleus. This effect strongly depends on the CtBP2 NLS. PXDLS motif-containing transcription factors, such as BKLF, that bind CtBP proteins can also direct them to the nucleus. We also report the identification of a splice isoform of CtBP2, CtBP2-S, that lacks the N-terminal NLS and localizes to the cytoplasm. Finally, we show that mutation of the CtBP NADH binding site impairs the ability of the proteins to dimerize and to associate with BKLF. This reduces the nuclear accumulation of CtBP1. Our results suggest a model in which the nuclear localization of CtBP proteins is influenced by the CtBP2 NLS, by binding to PXDLS motif partner proteins, and through the effect of NADH on CtBP dimerization.

scholarly journals Functional Identification of a Nuclear Localization Signal of MYB2 Protein in Giardia lamblia

2020 ◽  
Vol 58 (6) ◽  
pp. 675-679
Author(s):  
Juri Kim ◽  
Mee Young Shin ◽  
Soon-Jung Park
Keyword(s):  
Transcription Factor ◽  
Amino Acid ◽  
Nuclear Localization ◽  
Nuclear Import ◽  
Nuclear Localization Signal ◽  
Giardia Lamblia ◽  
Nuclear Protein ◽  
Functional Identification ◽  
Localization Signal ◽  
Nuclear Location

MYB2 protein was identified as a transcription factor that showed encystation-induced expression in <i>Giardia lamblia</i>. Although nuclear import is essential for the functioning of a transcription factor, an evident nuclear localization signal (NLS) of <i>G. lamblia</i> MYB2 (GlMYB2) has not been defined. Based on putative GlMYB2 NLSs predicted by 2 programs, a series of plasmids expressing hemagglutinin (HA)-tagged GlMYB2 from the promoter of <i>G. lamblia</i> glutamate dehydrogenase were constructed and transfected into Giardia trophozoites. Immunofluorescence assays using anti-HA antibodies indicated that GlMYB2 amino acid sequence #507–#530 was required for the nuclear localization of GlMYB2, and this sequence was named as NLS<sub>GlMYB2</sub>. We further verified this finding by demonstrating the nuclear location of a protein obtained by the fusion of NLS<sub>GlMYB2</sub> and <i>G. lamblia</i> glyceraldehyde 3-phosphate dehydrogenase, a non-nuclear protein. Our data on GlMYB2 will expand our understanding on NLSs functioning in <i>G. lamblia.</i>

Hsp105α suppresses Adriamycin‐induced cell death via nuclear localization signal‐dependent nuclear accumulation

2019 ◽  
Vol 120 (10) ◽  
pp. 17951-17962 ◽  
Author(s):  
Teppei Yamane ◽  
Youhei Saito ◽  
Hiroko Teshima ◽  
Mari Hagino ◽  
Ayana Kakihana ◽  
...  
Keyword(s):  
Cell Death ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Nuclear Accumulation ◽  
Localization Signal

scholarly journals The cell cycle-dependent nuclear import of v-Jun is regulated by phosphorylation of a serine adjacent to the nuclear localization signal.

1995 ◽  
Vol 130 (2) ◽  
pp. 255-263 ◽  
Author(s):  
T Tagawa ◽  
T Kuroki ◽  
P K Vogt ◽  
K Chida
Keyword(s):  
Cell Cycle ◽  
Nuclear Localization ◽  
Nuclear Import ◽  
Nuclear Localization Signal ◽  
Protein Kinase Inhibitors ◽  
Nuclear Accumulation ◽  
Dependent Manner ◽  
Localization Signal ◽  
Cycle Dependent

Cell cycle-dependent phosphorylation and nuclear import of the tumorigenic transcription factor viral Jun (v-Jun) were investigated in chicken embryo fibroblasts. Nuclear accumulation of v-Jun but not of cellular Jun (c-Jun) is cell cycle dependent, decreasing in G1 and increasing in G2. The cell cycle-dependent regulation of v-Jun was mapped to a single serine residue at position 248 (Ser248), adjacent to the nuclear localization signal (NLS). Ser248 of v-Jun represents an amino acid substitution, replacing cysteine of c-Jun. It was shown by peptidase digestion and immunoprecipitation with antibody to the NLS that v-Jun is phosphorylated at Ser248 in the cytoplasm but not in the nucleus. This phosphorylation is high in G1 and low in G2. Nuclear accumulation of v-Jun is correlated with underphosphorylation at Ser248. The regulation of nuclear import by phosphorylation was also examined using NLS peptides with Ser248 of v-Jun. Phosphorylation of the serine inhibited nuclear import mediated by the NLS peptide in vivo and in vitro. The protein kinase inhibitors staurosporine and H7 stimulated but the phosphatase inhibitor okadaic acid inhibited nuclear import mediated by the NLS peptide. The cytosolic activity of protein kinases phosphorylating Ser248 increased in G0 and decreased during cell cycle progression, reaching a minimum in G2, whereas phosphatase activity dephosphorylating Ser248 was not changed. These results show that nuclear import of v-Jun is negatively regulated by phosphorylation at Ser248 in the cytoplasm in a cell cycle-dependent manner.

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