scholarly journals Visualization of the Nuclear Lamina in Mouse Anterior Pituitary Cells and Immunocytochemical Detection of Lamin A/C by Quick-freeze Freeze-substitution Electron Microscopy

2005 ◽  
Vol 53 (4) ◽  
pp. 497-507 ◽  
Author(s):  
Takao Senda ◽  
Akiko Iizuka-Kogo ◽  
Atsushi Shimomura
Keyword(s):  
Electron Microscopy ◽  
Nuclear Membrane ◽  
Anterior Pituitary ◽  
Freeze Substitution ◽  
Nuclear Lamina ◽  
Immunogold Electron Microscopy ◽  
Lamin A ◽  
Pituitary Cells ◽  
Inner Nuclear Membrane ◽  
Anterior Pituitary Cells

We examined the nuclear lamina in the quickly frozen anterior pituitary cells by electron microscopic techniques combined with freeze substitution, deep etching, and immunocytochemistry and compared it with that in the chemically fixed cells. By quick-freeze freeze-substitution electron microscopy, an electron-lucent layer, as thick as 20 nm, was revealed just inside the inner nuclear membrane, whereas in the conventionally glutaraldehyde-fixed cells the layer was not seen. By quick-freeze deep-etch electron microscopy, we could not distinguish definitively the layer corresponding to the nuclear lamina in either fresh unfixed or glutaraldehyde-fixed cells. Immunofluorescence microscopy showed that lamin A/C in the nucleus was detected in the acetone-fixed cells and briefly in paraformaldehyde-fixed cells but not in the cells with prolonged paraformaldehyde fixation. Nuclear localization of lamin A/C was revealed by immunogold electron microscopy also in the quickly frozen and freeze-substituted cells, but not in the paraformaldehyde-fixed cells. Lamin A/C was localized mainly in the peripheral nucleoplasm within 60 nm from the inner nuclear membrane, which corresponded to the nuclear lamina. These results suggest that the nuclear lamina can be preserved both ultrastructurally and immunocytochemically by quick-freezing fixation, rather than by conventional chemical fixation.

Dopamine enters lactotrophs and reaches their secretory granules

1985 ◽  
Vol 104 (1) ◽  
pp. 23-NP ◽  
Author(s):  
M. G. P. Gallardo ◽  
M. Bilinski ◽  
S. R. Chiocchio ◽  
J. H. Tramezzani
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Anterior Pituitary ◽  
Secretory Granules ◽  
Pituitary Cells ◽  
Histochemical Reaction ◽  
Anterior Pituitary Cells ◽  
Biochemical Assays ◽  
Pituitary Lactotroph

ABSTRACT The presence of dopamine in the lactotroph cell, as well as in isolated prolactin secretory granules, was demonstrated by means of an histochemical reaction for electron microscopy. Biochemical assays further confirmed the presence of dopamine in the secretory granules. Autoradiographic preparations examined by light microscopy showed dopamine internalization in dispersed anterior pituitary cells. Isolated anterior pituitary lactotroph cells incorporated more [3H]dopamine than a fraction containing other anterior pituitary cells. J. Endocr. (1985) 104, 23–28

scholarly journals The nuclear lamina is a hub for the nuclear function of Jacob

2020 ◽  
Author(s):  
Sebastian Samer ◽  
Rajeev Raman ◽  
Gregor Laube ◽  
Michael R. Kreutz ◽  
Anna Karpova
Keyword(s):  
Gene Expression ◽  
Nuclear Membrane ◽  
Nuclear Import ◽  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Nuclear Lamina ◽  
Immunogold Electron Microscopy ◽  
Core Component ◽  
Inner Nuclear Membrane ◽  
Export Signal

Abstract Jacob is a synapto-nuclear messenger protein that couples NMDAR activity to CREB-dependent gene expression. In this study, we investigated the nuclear distribution of Jacob and report a prominent targeting to the nuclear envelope that requires NMDAR activity and nuclear import. Immunogold electron microscopy revealed preferential association of Jacob with the inner nuclear membrane where it directly binds to LaminB1, an intermediate filament and core component of the inner nuclear membrane (INM). The association with INM is transient; it involves a functional nuclear export signal in Jacob and a canonical CRM1-/RanGTP-dependent export mechanism that defines the residing time of the protein at the INM. Taken together, the data suggest a stepwise redistribution of Jacob within the nucleus following nuclear import and prior to nuclear export.

scholarly journals Extragenic Suppression of a Mutation in Herpes Simplex Virus 1 UL34 That Affects Lamina Disruption and Nuclear Egress

2016 ◽  
Vol 90 (23) ◽  
pp. 10738-10751 ◽  
Author(s):  
Amber Vu ◽  
Chelsea Poyzer ◽  
Richard Roller
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Nuclear Membrane ◽  
Nuclear Lamina ◽  
Nuclear Shape ◽  
Lamin A ◽  
Herpes Simplex Virus 1 ◽  
Inner Nuclear Membrane ◽  
Nuclear Egress ◽  
Simplex Virus

ABSTRACT Nuclear egress of herpesviruses is accompanied by changes in the architecture of the nuclear membrane and nuclear lamina that are thought to facilitate capsid access to the inner nuclear membrane (INM) and curvature of patches of the INM around the capsid during budding. Here we report the properties of a point mutant of pUL34 (Q163A) that fails to induce gross changes in nuclear architecture or redistribution of lamin A/C. The UL34(Q163A) mutant shows a roughly 100-fold defect in single-step growth, and it forms small plaques. This mutant has a defect in nuclear egress, and furthermore, it fails to disrupt nuclear shape or cause observable displacement of lamin A/C despite retaining the ability to recruit the pUS3 and PKC protein kinases and to mediate phosphorylation of emerin. Extragenic suppressors of the UL34(Q163A) phenotype were isolated, and all of them carry a single mutation of arginine 229 to leucine in UL31. Surprisingly, although this UL31 mutation largely restores virus replication, it does not correct the lamina disruption defect, suggesting that, in Vero cells, changes in nuclear shape and gross displacements of lamin A/C may facilitate but are unnecessary for nuclear egress. IMPORTANCE Herpesvirus nuclear egress is an essential and conserved process that requires close association of the viral capsid with the inner nuclear membrane and budding of the capsid into that membrane. Access to the nuclear membrane and tight curvature of that membrane are thought to require disruption of the nuclear lamina that underlies the inner nuclear membrane, and consistent with this idea, herpesvirus infection induces biochemical and architectural changes at the nuclear membrane. The significance of the nuclear membrane architectural changes is poorly characterized. The results presented here address that deficiency in our understanding and show that a combination of mutations in two of the viral nuclear egress factors results in a failure to accomplish at least two components of lamina disruption while still allowing relatively efficient viral replication, suggesting that changes in nuclear shape and displacement of lamins are not necessary for herpes simplex virus 1 (HSV-1) nuclear egress.

Surface morphology and secretory activity of rat anterior pituitary cells in primary culture

1978 ◽  
Vol 36 (2) ◽  
pp. 584-585
Author(s):  
T. Antakly ◽  
F. Zeytinoglu ◽  
G. Pelletier ◽  
F. Labrie
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Morphology ◽  
Primary Culture ◽  
Anterior Pituitary ◽  
Secretory Activity ◽  
Secretory Cells ◽  
Pituitary Cells ◽  
Anterior Pituitary Cells ◽  
Scanning Electron

So far, there has been no report concerning the surface morphology of cultured secretory cells in different states of activity, as observed by scanning electron microscopy. The anterior pituitary cells in monolayer culture offer an unique system to study the modifications of cell conformation in relation with changes of activity since these cells can be specifically modulated by stimulating or inhibiting factors. Scanning electron microscopy of anterior pituitary cells in primary culture was thus performed in different states of secretory activity. Adult female Sprague-Dawley rats at random stage of the estrous cycle, were used for the preparation of the primary cultures of anterior pituitary cells as previously described (Endocrinology 98: 1528, 1976). The cells 7. 5 x 105 in 1. 5 ml of Dulbecco's modified Eagle's medium containing 10% horse serum and 0. 25% foetal calf serum were plated in 3. 5 x 10 mm Petri dishes and were used six days after plating.

scholarly journals A study of acid phosphatase and dipeptidyl aminopeptidase II in monodispersed anterior pituitary cells using flow cytometry and electron microscopy.

1979 ◽  
Vol 27 (11) ◽  
pp. 1499-1504 ◽  
Author(s):  
R E Smith ◽  
P N Dean
Keyword(s):  
Electron Microscopy ◽  
Flow Cytometry ◽  
Acid Phosphatase ◽  
Anterior Pituitary ◽  
Single Cells ◽  
Fluorescent Microscopy ◽  
Historical Review ◽  
Pituitary Cells ◽  
Anterior Pituitary Cells ◽  
Dipeptidyl Aminopeptidase

A brief historical review of cytoenzymology is presented from the time of introduction into electron microscopy to the present, where the direction for quantification of an enzyme in single cells appears most promising by fluorescent staining. First attempts are reported to quantitate acid phosphatase (AcPase) and dipeptidyl aminopeptidase II (DAP-II) in monodispersed anterior pituitary cells from lactating and postlactating rats by flow cytometry, fluorescent, and electron microscopy. 3-Hydroxy-flavone is introduced as a new fluorescent cytochemical stain for AcPase, useful in flow cytometry but of only limited use in fluorescent microscopy. Histograms for AcPase indicate a single peak of cells staining more intensely in cell preparations from postlactating over lactating animals. Histograms for DAP-II staining indicate two distinct populations of cells present in the lactating and only one in the postlactating rat anterior pituitary gland. The application of dual laser staining indicates that not all cells stain for both enzymes. Electron microscopy shows the subcellular localization of DAP-II to be limited to lytic bodies and in mammotrophic cells to some secretion granules.

scholarly journals The nuclear lamina is a hub for the nuclear function of Jacob

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Sebastian Samer ◽  
Rajeev Raman ◽  
Gregor Laube ◽  
Michael R. Kreutz ◽  
Anna Karpova
Keyword(s):  
Nuclear Membrane ◽  
Nuclear Import ◽  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Nuclear Lamina ◽  
Proximity Ligation Assay ◽  
Immunogold Electron Microscopy ◽  
Inner Nuclear Membrane ◽  
Proximity Ligation ◽  
Export Signal

AbstractJacob is a synapto-nuclear messenger protein that couples NMDAR activity to CREB-dependent gene expression. In this study, we investigated the nuclear distribution of Jacob and report a prominent targeting to the nuclear envelope that requires NMDAR activity and nuclear import. Immunogold electron microscopy and proximity ligation assay combined with STED imaging revealed preferential association of Jacob with the inner nuclear membrane where it directly binds to LaminB1, an intermediate filament and core component of the inner nuclear membrane (INM). The association with the INM is transient; it involves a functional nuclear export signal in Jacob and a canonical CRM1-RanGTP-dependent export mechanism that defines the residing time of the protein at the INM. Taken together, the data suggest a stepwise redistribution of Jacob within the nucleus following nuclear import and prior to nuclear export.

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