sh.sePublikationer
Ändra sökning
Avgränsa sökresultatet
1 - 7 av 7
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • harvard-anglia-ruskin-university
  • apa-old-doi-prefix.csl
  • sodertorns-hogskola-harvard.csl
  • sodertorns-hogskola-oxford.csl
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Imreh, Gabriela
    et al.
    Stockhlms univeristet.
    Beckman, M.
    Stockholms universitet.
    Iverfeldt, K.
    Stockholms universitet.
    Hallberg, Einar
    Stockholms universitet.
    Noninvasive monitoring of apoptosis versus necrosis in a neuroblastoma cell line expressing a nuclear pore protein tagged with the green fluorescent protein1998Ingår i: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 238, nr 2, s. 371-376Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A fusion chimera between the integral nuclear pore membrane protein POM121 and GFP (green fluorescent protein) has been shown to correctly target to the nuclear pores when transiently expressed in a number of mammalian cell types. POM121-GFP is therefore an excellent marker for the noninvasive studies of the nuclear pores in living cells using fluorescence microscopy. We have established a line of neuroblastoma cells stably expressing the POM121-GFP fusion protein. We also monitored the nuclear envelope in living cells after induction of apoptosis or necrosis using 1 μM staurosporine or 100 μM p-benzoquinone, respectively. Interestingly, the POM121-GFP fluorescence was weaker or missing in the apoptotic cells. The disappearance of the nuclear pore marker accompanied apoptotic progression as judged by the degree of chromatin condensation and DNA fragmentation as analyzed by DNA staining and TUNEL assay, respectively. In contrast, the intensity of the nuclear rim fluorescence was unaffected in necrotic cells displaying an abnormal morphology with tilted nuclei. Thus, it was possible to distinguish between apoptotic and necrotic development in living cells using fluorescence microscopy. This cell line provides a fast and convenient model for screening suspected toxic xenobiotics.

  • 2.
    Imreh, Gabriela
    et al.
    Södertörns högskola, Avdelning Naturvetenskap. Stockholm University.
    Hallberg, Einar
    Södertörns högskola, Avdelning Naturvetenskap.
    An integral membrane protein from the nuclear pore complex is also present in the annulate lamellae: Implications for annulate lamella formation2000Ingår i: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 259, nr 1, s. 180-190Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Annulate lamellae (AL) are cytoplasmic arrays of stacked membrane cisternae containing densely packed pore complexes which are similar in structure to the nuclear pore complexes (NPCs) and thus referred to as annulate lamella pore complexes (ALPCs). We have recently shown that the integral nuclear pore membrane protein POM121 tagged with green fluorescent protein was correctly targeted to the nuclear pores (H. Soderqvist et al., 1997, fur. J. Biochem. 250, 808-813). Here we have investigated if POM121 fused to three tandem molecules of yellow fluorescent protein YFP) (POM121-YFP3,) also was able to distribute in the extensive and well-characterized Al; of RC37 and BMGE cells. Transfected RC37 or BMGE cells displayed YFP fluorescence around the nuclear envelope, as well. as in the cytoplasmic AL structures. The YFP fluorescence colocalized perfectly with immunostaining using antibodies specific for different NPC proteins. The AL of both transfected and untransfected BMGE cells resisted extractions with Tx-100 and 250 mM NaCl, but were completely solubilized at 450 mM NaCl. Loss of YFP fluorescence and immunostaining for other NPC proteins correlated under all extraction conditions tested, suggesting that overexpressed POM121-YFP3, had become an integrated part both of the NPCs and of the ALPCs. Furthermore, we have generated a stable BHK cell line expressing POM121YFP(3,) located exclusively at the nuclear pores. Treatment with vinblastine sulfate, which induces formation of Al; in a variety of cells, resulted in distribution of POM121-YFP3, into cytoplasmic foci colocalizing with immunostaining for peripheral NPC proteins. Taken together, the results show that YFP-tagged POM121 is able to distribute in drug-induced or naturally occurring AL, suggesting that POM121 is a natural constituent of ALPCs. In COS cells, which normally lack or have very little AT-I, YFP-tagged POM121 distributed in the nuclear pores when expressed at low levels. However, at high expression levels the YFP fluorescence also distributed in a number of brightly fluorescing cytoplasmic dots or foci, which were not present in untransfected cells. This was also true for untagged POM121. The cytoplasmic foci varied in size from 0.1 to 2 mu m and were distinctly located in the immediate vicinity of ER cisternae (without colocalizing) and also contained other nuclear pore proteins, indicating that they may represent cytoplasmic AL. This idea is supported by time-lapse studies of postmitotic assembly of these structures. This raises the question of the role of POM121 in ALPC and NPC biogenesis.

  • 3.
    Imreh, Gabriela
    et al.
    Södertörns högskola, Avdelning Naturvetenskap. Stockholm University.
    Maksel, Danuta
    Södertörns högskola, Avdelning Naturvetenskap.
    de Monvel, J B
    Branden, L
    Hallberg, Einar
    Södertörns högskola, Avdelning Naturvetenskap.
    ER retention may play a role in sorting of the nuclear pore membrane protein POM1212003Ingår i: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 284, nr 2, s. 173-184Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Integral membrane proteins of the nuclear envelope (NE) are synthesized on the rough endoplasmic reticulum (ER) and following free diffusion in the continuous ER/NE membrane system are targeted to their proper destinations due to interactions of specific domains with other components of the NE. By studying the intracellular distribution and dynamics of a deletion mutant of an integral membrane protein of the nuclear pores, POM121, which lacks the pore-targeting domain, we investigated if ER retention plays a role in sorting of integral membrane proteins to the nuclear envelope. A nascent membrane protein lacking sorting determinants is believed to diffuse laterally in the continuous ER/NE lipid bilayer and expected to follow vesicular traffic to the plasma membrane. The GFP-tagged deletion mutant, POM121(1-129)-GFP, specifically distributed within the ER membrane, but was completely absent from the Golgi compartment and the plasma membrane. Experiments using fluorescence recovery after photobleaching (FRAP) and fluorescence loss in photobleaching (FLIP) demonstrated that despite having very high mobility within the whole ER network (D = 0.41 +/- 0.11 mum(2)/s) POM121(1-129)-GFP was unable to exit the ER. It was also not detected in post-ER compartments of cells incubated at 15degreesC. Taken together, these experiments show that amino acids 1-129 of POM121 are able to retain GFP in the ER membrane and suggest that this retention occurs by a direct mechanism rather than by a retrieval mechanism. Our data suggest that ER retention might be important for sorting of POM121 to the nuclear pores.

  • 4.
    Kihlmark, Madeleine
    et al.
    Södertörns högskola, Institutionen för kemi, biologi, geografi och miljövetenskap. Stockholm University.
    Rustum, Cecilia
    Södertörns högskola, Institutionen för kemi, biologi, geografi och miljövetenskap. Stockholm University.
    Eriksson, Charlotta
    Södertörns högskola, Institutionen för kemi, biologi, geografi och miljövetenskap. Karolinska Institutet.
    Beckman, M
    Stockholm University.
    Iverfeldt, K
    Stockholm University.
    Hallberg, Einar
    Södertörns högskola, Institutionen för kemi, biologi, geografi och miljövetenskap.
    Correlation between nucleocytoplasmic transport and caspase-3-dependent dismantling of nuclear pores during apoptosis2004Ingår i: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 293, nr 2, s. 346-356Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    During apoptosis (also called programmed cell death), the chromatin condenses and the DNA is cleaved into oligonucleosomal fragments. Caspases are believed to play a major role in nuclear apoptosis. However, the relation between dismantling of nuclear pores, disruption of the nucleocytoplasmic barrier, and nuclear entry of caspases is unclear. We have analyzed nuclear import of the green fluorescent protein fused to a nuclear localization signal (GFP-NLS) in tissue culture cells undergoing apoptosis. Decreased nuclear accumulation of GFP-NLS could be detected at the onset of nuclear apoptosis manifested as dramatic condensation and redistribution of chromatin toward the nuclear periphery. At this step, dismantling of nuclear pores was already evident as indicated by proteolysis of the nuclear pore membrane protein POM121. Thus, disruption of nuclear compartmentalization correlated with early signs of nuclear pore damage. Both these events clearly preceded massive DNA fragmentation, detected by TUNEL assay. Furthermore, we show that in apoptotic cells, POM121 is specifically cleaved at aspartate-531 in its large C-terminal portion by a caspase-3-dependent mechanism. Cleavage of the C-terminal portion of POM121, which is adjoining the nuclear pore complex, is likely to disrupt interactions with other nuclear pore proteins affecting the stability of the pore complex. A temporal correlation of apoptotic events supports a model where caspase-dependent disassembly of nuclear pores and disruption of the nucleocytoplasmic barrier paves the way for nuclear entry of caspases and subsequent activation of CAD-mediated DNA fragmentation.

  • 5.
    Olsson, Ida
    et al.
    Södertörns högskola, Institutionen för livsvetenskaper.
    Berrez, Jean-Marc
    Södertörns högskola, Institutionen för livsvetenskaper.
    Leipus, Arunas
    CHORI, Children's Hospital Oakland Research Institute, Oakland, USA / Umeå University.
    Östlund, Cecilia
    Columbia University, New York, USA.
    Mutvei, Ann
    Södertörns högskola, Institutionen för livsvetenskaper.
    The arginine methyltransferase Rmt2 is enriched in the nucleus and co-purifies with the nuclear porins Nup49, Nup57 and Nup1002007Ingår i: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 313, nr 9, s. 1778-1789Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Arginine methylation is a post-translational modification of proteins implicated in RNA processing, protein compartmentalization, signal transduction, transcriptional regulation and DNA repair. In a screen for proteins associated with the nuclear envelope in the yeast Saccharomyces cerevisiae, we have identified the arginine methyltransferase Rmt2, previously shown to methylate the ribosomal protein L12. By indirect immunofluorescence and subcellular fractionations we demonstrate here that Rmt2 has nuclear and cytoplasmic localizations. Biochemical analysis of a fraction enriched in nuclei reveals that nuclear Rmt2 is resistant to extractions with salt and detergent, indicating an association with structural components. This was supported by affinity purification experiments with TAP-tagged Rmt2. Rmt2 was found to co-purify with the nucleoporins Nup49, Nup57 and Nup100, revealing a novel link between arginine methyltransferases and the nuclear pore complex. In addition, a genome-wide transcription study of the rmt2 Delta mutant shows significant downregulation of the transcription of MYO1, encoding the Type II myosin heavy chain required for cytokinesis and cell separation.

  • 6.
    Onischenko, Evgeny A.
    et al.
    Södertörns högskola, Institutionen för livsvetenskaper. Karolinska Institute.
    Crafoord, Ellinor
    Södertörns högskola, Institutionen för livsvetenskaper. Karolinska Institute.
    Hallberg, Einar
    Södertörns högskola, Institutionen för livsvetenskaper.
    Phosphomimetic mutation of the mitotically phosphorylated serine 1880 compromises the interaction of the transmembrane nucleoporin gp210 with the nuclear pore complex2007Ingår i: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 313, nr 12, s. 2744-2751Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The nuclear pore complexes (NPCs) reversibly disassemble and reassemble during mitosis. Disassembly of the NPC is accompanied by phosphorylation of many nucleoporins although the function of this is not clear. It was previously shown that in the transmembrane nucleoporin gp210 a single serine residue at position 1880 is specifically phosphorylated during mitosis. Using amino acid substitution combined with live cell imaging, time-lapse microscopy and FRAP, we investigated the role of serine 1880 in binding of gp210 to the NPC in vivo An alanine subtitutions mutant (S1880A) was significantly more dynamic at the NPC compared to the wild-type protein, suggesting that serine 1880 is important for binding of gp210 to the NPC. Moreover a glutamate substitution (S1880E) closely mimicking phosphorylated serine specifically interfered with incorporation of gp210 into the NPC and compromised its post-mitotic recruitment to the nuclear envelope of daughter nuclei. our findings are consistent with the idea that mitotic phosphorylation acts to dissociate gp210 from the structural elements of the NPC.

  • 7.
    Persson, Jenna
    et al.
    Karolinska Institutet.
    Ekwall, Karl
    Södertörns högskola, Institutionen för livsvetenskaper, Molekylärbiologi. Karolinska Institutet.
    Chd1 remodelers maintain open chromatin and regulate the epigenetics of differentiation2010Ingår i: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 316, nr 8, s. 1316-1323Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Eukaryotic DNA is packaged around octamers of histone proteins into nucleosomes, the basic unit of chromatin. In addition to enabling meters of DNA to fit within the confines of a nucleus, the structure of chromatin has functional implications for cell identity. Covalent chemical modifications to the DNA and to histones, histone variants, ATP-dependent chromatin remodelers, small noncoding RNAs and the level of chromatin compaction all contribute to chromosomal structure and to the activity or silencing of genes. These chromatin-level alterations are defined as epigenetic when they are heritable from mother to daughter cell. The great diversity of epigenomes that can arise from a single genome permits a single, totipotent cell to generate the hundreds of distinct cell types found in humans. Two recent studies in mouse and in fly have highlighted the importance of Chd1 chromatin remodelers for maintaining an open, active chromatin state. Based on evidence from fission yeast as a model system, we speculate that Chd1 remodelers are involved in the disassembly of nucleosomes at promoter regions, thus promoting active transcription and open chromatin. It is likely that these nucleosomes are specifically marked for disassembly by the histone variant H2A.Z.

1 - 7 av 7
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • harvard-anglia-ruskin-university
  • apa-old-doi-prefix.csl
  • sodertorns-hogskola-harvard.csl
  • sodertorns-hogskola-oxford.csl
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf