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>

Nuclear import of glycoconjugates is distinct from the classical NLS pathway

1995 ◽  
Vol 108 (4) ◽  
pp. 1325-1332 ◽  
Author(s):  
E. Duverger ◽  
C. Pellerin-Mendes ◽  
R. Mayer ◽  
A.C. Roche ◽  
M. Monsigny
Keyword(s):  
Nuclear Localization ◽  
Nuclear Import ◽  
Nuclear Localization Signal ◽  
Peptide Sequence ◽  
Nuclear Pore ◽  
Dependent Manner ◽  
Permeabilized Cells ◽  
Localization Signal ◽  
Energy Dependent ◽  
Cytosolic Factors

The nuclear import of many proteins depends on a short peptide sequence called the nuclear localization signal. However, glycosylated proteins, which lack such a nuclear localization signal, upon their injection into the cytosol by electroporation, enter the nucleus in a sugar-dependent manner. This paper brings new insights on the mechanism of this process, based on a study of neoglycoprotein nuclear uptake by digitonin-permeabilized cells. The nuclear import of neoglycoproteins is energy dependent: it does not occur when cells are maintained at 4 degrees C or when cells are ATP-depleted by treatment with apyrase. The nuclear import of neoglycoproteins occurs through the nuclear pore: it is inhibited by preincubation of cells with wheat germ agglutinin, a lectin which binds the nuclear pore glycoproteins and blocks the translocation step of nuclear localization signal bearing proteins through the nuclear pore. Furthermore, the nuclear import of neoglycoproteins does not use the pathway of nuclear localization signal bearing proteins: nuclear import of nuclear localization signal bearing proteins depends on cytosolic factors and is inhibited by treatment of cells with N-ethylmaleimide, while the nuclear import of neoglycoproteins neither requires added cytosolic factors nor is sensitive to alkylation by N-ethylmaleimide. In addition, upon incubation in the presence of a large excess of nuclear localization signal bearing protein, the nuclear import of neoglycoproteins is not inhibited.

Hairless is translocated to the nucleus via a novel bipartite nuclear localization signal and is associated with the nuclear matrix

2001 ◽  
Vol 114 (2) ◽  
pp. 367-376
Author(s):  
K. Djabali ◽  
V.M. Aita ◽  
A.M. Christiano
Keyword(s):  
Amino Acid ◽  
Hair Follicle ◽  
Nuclear Localization ◽  
Nuclear Matrix ◽  
Nuclear Localization Signal ◽  
Amino Acid Residues ◽  
Bipartite Nuclear Localization Signal ◽  
Hairless Gene ◽  
Fractionation Analysis ◽  
Localization Signal

Hair follicle cycling is an exquisitely regulated and dynamic process consisting of phases of growth, regression and quiescence. The transitions between the phases are governed by a growing number of regulatory proteins, including transcription factors. The hairless (hr) gene encodes a putative transcription factor that is highly expressed in the skin, where it appears to be an essential regulator during the regression of the catagen hair follicle. In hairless mice, as well as humans with congenital atrichia, the absence of hr gene function initiates a premature and abnormal catagen due to a dysregulation of apoptosis and cell adhesion, and defects in the signaling required for hair follicle remodeling. Here, we report structure-function studies of the hairless gene product, in which we identify a novel bipartite nuclear localization signal (NLS) of the form KRA(X13) PKR. Deletion analysis of the mouse hr gene mapped the NLS to amino acid residues 409–427. Indirect immunofluorescence microscopy of cells transiently transfected with hairless-green fluorescent fusion proteins demonstrated that these amino acid residues are necessary and sufficient for nuclear localization. Furthermore, nuclear fractionation analysis revealed that the hr protein is associated with components of the nuclear matrix.

Nuclear transport of the U2 snRNP-specific U2B'' protein is mediated by both direct and indirect signalling mechanisms

1994 ◽  
Vol 107 (7) ◽  
pp. 1807-1816 ◽  
Author(s):  
C. Kambach ◽  
I.W. Mattaj
Keyword(s):  
Nuclear Localization ◽  
Nuclear Import ◽  
Nuclear Localization Signal ◽  
Nuclear Transport ◽  
U2 Snrna ◽  
Central Segment ◽  
U2 Snrnp ◽  
U1 Snrnp ◽  
Localization Signal ◽  
Protein Amino Acids

Experiments investigating the nuclear import of the U2 snRNP-specific B'' protein (U2B'') are presented. U2B'' nuclear transport is shown to be able to occur independently of binding to U2 snRNA. The central segment of the protein (amino acids 90–146) encodes an unusual nuclear localization signal (NLS) that is related to that of the U1 snRNP-specific A protein. However, nuclear import of U2B'' does not depend on this NLS. Sequences in the N-terminal RNP motif of the protein are sufficient to direct nuclear transport, and evidence is presented that the interaction of U2B'' with the U2A' protein mediates this effect. This suggests that U2B'' can ‘piggy-back’ to the nucleus in association with U2A’, and thus be imported to the nucleus by two different mechanisms. U2A' nuclear transport, on the other hand, can occur independently of both U2B'' binding and of U2 snRNA.

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

Use of a general purpose mammalian expression vector for studying intracellular protein targeting: identification of critical residues in the nuclear lamin A/C nuclear localization signal

1993 ◽  
Vol 105 (2) ◽  
pp. 481-488 ◽  
Author(s):  
J.V. Frangioni ◽  
B.G. Neel
Keyword(s):  
Amino Acid ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Protein Targeting ◽  
General Purpose ◽  
Expression Vectors ◽  
Intracellular Protein ◽  
Mammalian Expression ◽  
Nuclear Lamin ◽  
Localization Signal

We have constructed a general purpose mammalian expression vector for the study of intracellular protein targeting. The vector, p3PK, facilitates construction of N- and/or C-terminal fusions of an amino acid sequence of interest to the normally cytosolic protein chicken muscle pyruvate kinase (CMPK). The vector has been engineered such that any fusion construct can be subcloned into the versatile pJx omega family of mammalian expression vectors and into pGEX bacterial expression vectors, for the generation of affinity reagents. In this paper, we demonstrate the general utility of p3PK by redirecting CMPK to mitochondria (using the twelve amino acid pre-sequence of yeast cytochrome c oxidase subunit IV) and to the nucleus (using a putative eight amino acid nuclear localization signal from human nuclear lamins A and C). We also report that, contrary to the predictions of previously published work, substitution of a critical residue in the nuclear lamin A/C nuclear localization signal (the equivalent of lysine 128 in the SV40 large T nuclear localization signal) retains nuclear localization, and discuss how amino acid context might affect targeting to the nucleus.

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.

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