Faculty Opinions recommendation of A potential role for human cohesin in mitotic spindle aster assembly.

2001 ◽  
Author(s):  
Timothy Yen
Keyword(s):  
Mitotic Spindle ◽  
Potential Role

scholarly journals A Potential Role for Human Cohesin in Mitotic Spindle Aster Assembly

2001 ◽  
Vol 276 (50) ◽  
pp. 47575-47582 ◽  
Author(s):  
Heather C. Gregson ◽  
John A. Schmiesing ◽  
Jong-Soo Kim ◽  
Toshiki Kobayashi ◽  
Sharleen Zhou ◽  
...  
Keyword(s):  
Sister Chromatid ◽  
Mitotic Spindle ◽  
Potential Role ◽  
Metaphase Plate ◽  
Spindle Pole ◽  
Sister Chromatid Cohesion ◽  
Cycle Arrest ◽  
Spindle Poles ◽  
Chromatid Cohesion

The cohesin multiprotein complex containing SMC1, SMC3, Scc3 (SA), and Scc1 (Rad21) is required for sister chromatid cohesion in eukaryotes. Although metazoan cohesin associates with chromosomes and was shown to function in the establishment of sister chromatid cohesion during interphase, the majority of cohesin was found to be off chromosomes and reside in the cytoplasm in metaphase. Despite its dissociation from chromosomes, however, microinjection of an antibody against human SMC1 led to disorganization of the metaphase plate and cell cycle arrest, indicating that human cohesin still plays an important role in metaphase. To address the mitotic function of human cohesin, the subcellular localization of cohesin components was reexamined in human cells. Interestingly, we found that cohesin localizes to the spindle poles during mitosis and interacts with NuMA, a spindle pole-associated factor required for mitotic spindle organization. The interaction with NuMA persists during interphase. Similar to NuMA, a significant amount of cohesin was found to associate with the nuclear matrix. Furthermore, in the absence of cohesin, mitotic spindle asters failed to formin vitro. Our results raise the intriguing possibility that in addition to its well demonstrated function in sister chromatid cohesion, cohesin may be involved in spindle assembly during mitosis.

scholarly journals Chaperone-like activity of the AAA+ proteins Rvb1 and Rvb2 in the assembly of various complexes

2013 ◽  
Vol 368 (1617) ◽  
pp. 20110399 ◽  
Author(s):  
Nardin Nano ◽  
Walid A. Houry
Keyword(s):  
Protein Kinase ◽  
Mitotic Spindle ◽  
Potential Role ◽  
Histone Acetyltransferase ◽  
Related Protein ◽  
Phosphatidylinositol 3 Kinase ◽  
Cellular Processes ◽  
Wide Range ◽  
Mitotic Spindle Assembly

Rvb1 and Rvb2 are highly conserved and essential eukaryotic AAA+ proteins linked to a wide range of cellular processes. AAA+ proteins are ATPases associated with diverse cellular activities and are characterized by the presence of one or more AAA+ domains. These domains have the canonical Walker A and Walker B nucleotide binding and hydrolysis motifs. Rvb1 and Rvb2 have been found to be part of critical cellular complexes: the histone acetyltransferase Tip60 complex, chromatin remodelling complexes Ino80 and SWR-C, and the telomerase complex. In addition, Rvb1 and Rvb2 are components of the R2TP complex that was identified by our group and was determined to be involved in the maturation of box C/D small nucleolar ribonucleoprotein (snoRNP) complexes. Furthermore, the Rvbs have been associated with mitotic spindle assembly, as well as phosphatidylinositol 3-kinase-related protein kinase (PIKK) signalling. This review sheds light on the potential role of the Rvbs as chaperones in the assembly and remodelling of these critical complexes.

Structural Studies on Mitotic Spindle Fibres

1978 ◽  
Vol 36 (3) ◽  
pp. 615-626
Author(s):  
J.R. Mcintosh
Keyword(s):  
Chemical Composition ◽  
Mitotic Spindle ◽  
Structural Studies ◽  
Mitotic Apparatus ◽  
Chemical Studies ◽  
Medical Interest ◽  
Spindle Fibres

The mitotic apparatus is a structure of obvious biological and medical interest, but it has proved to be a difficult cellular machine to understand. The chemical composition of the spindle is only slightly elucidated, largely because of the difficulties in preparing useful isolates of the structure. Chemical studies of the mitotic spindle have been reviewed elsewhere (Mcintosh, 1977), and will not be discussed further here. One would think that structural studies on the mitotic apparatus (MA) in situ would be straightforward, but even with this approach there is some disagreement in the results obtained with various methods and by different investigators. In this paper I will review briefly the approaches which have been used in structural studies of the MA, pointing out the strengths and problems of each approach. I will summarize the principal findings of the different methods, and identify what seem to be fruitful avenues for further work.

Filaments and membranes in the mitotic apparatus

1983 ◽  
Vol 41 ◽  
pp. 544-547
Author(s):  
Kent McDonald
Keyword(s):  
Intermediate Filaments ◽  
Mitotic Spindle ◽  
Mitotic Apparatus ◽  
Light Microscope Level ◽  
Microtubule Associated Proteins ◽  
Recent Developments ◽  
Associated Proteins ◽  
Force Generator ◽  
Spindle Function ◽  
Antibody Technology

At the light microscope level the recent developments and interest in antibody technology have permitted the localization of certain non-microtubule proteins within the mitotic spindle, e.g., calmodulin, actin, intermediate filaments, protein kinases and various microtubule associated proteins. Also, the use of fluorescent probes like chlorotetracycline suggest the presence of membranes in the spindle. Localization of non-microtubule structures in the spindle at the EM level has been less rewarding. Some mitosis researchers, e.g., Rarer, have maintained that actin is involved in mitosis movements though the bulk of evidence argues against this interpretation. Others suggest that a microtrabecular network such as found in chromatophore granule movement might be a possible force generator but there is little evidence for or against this view. At the level of regulation of spindle function, Harris and more recently Hepler have argued for the importance of studying spindle membranes. Hepler also believes that membranes might play a structural or mechanical role in moving chromosomes.

Quantitative ultrastructural reconstruction of small regions within large volumes by correlative light and high voltage electron microscopy of serial 0.25-0.50 μm sections

1987 ◽  
Vol 45 ◽  
pp. 578-581
Author(s):  
Conly L. Rieder ◽  
Frederick J. Miller ◽  
Edwin Davison ◽  
Samuel S. Bowser ◽  
Kirsten Lewis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Mitotic Spindle ◽  
Meiotic Spindle ◽  
High Voltage Electron Microscopy ◽  
Male And Female ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Differential Stability ◽  
Sperm Aster

In this abstract we Illustrate how same-section correlative light and high voltage electron microscopy (HVEM) of serial 0.25-0.50-μm sections can answer questions which are difficult to approach by EM of 60-100 nm sections.Starfish (Pisaster and Asterlas) eggs are fertilized at meiosis I when the oocyte contains two maternal centrosomes (e.g., asters) which form the poles of the first meiotic spindle. Immediately after fertilization a sperm aster is assembled in the vicinity of the male pronucleus and persists throughout meiosis. At syngamy the sperm aster splits to form the poles of the first mitotic spindle. During this time the functional and replicative properties of the maternal centrosome, inherited from the last meiotic division, are lost. The basis for this differential stability, of male and female centrosomes in the same cytoplasm, is a mystery.

Modulated polarization microscopy displays the dynamics of cytoskeletal structures in living, motile cells

1995 ◽  
Vol 53 ◽  
pp. 902-903
Author(s):  
J. R. Kuhn ◽  
M. Poenie
Keyword(s):  
Mitotic Spindle ◽  
Actin Filaments ◽  
Cell Shape ◽  
Dynamic Structure ◽  
Living Cells ◽  
Cytoskeletal Proteins ◽  
Polarization Microscopy ◽  
Video Enhancement ◽  
Ultrastructural Studies ◽  
Motile Cells

Cell shape and movement are controlled by elements of the cytoskeleton including actin filaments an microtubules. Unfortunately, it is difficult to visualize the cytoskeleton in living cells and hence follow it dynamics. Immunofluorescence and ultrastructural studies of fixed cells while providing clear images of the cytoskeleton, give only a static picture of this dynamic structure. Microinjection of fluorescently Is beled cytoskeletal proteins has proved useful as a way to follow some cytoskeletal events, but long terry studies are generally limited by the bleaching of fluorophores and presence of unassembled monomers.Polarization microscopy has the potential for visualizing the cytoskeleton. Although at present, it ha mainly been used for visualizing the mitotic spindle. Polarization microscopy is attractive in that it pro vides a way to selectively image structures such as cytoskeletal filaments that are birefringent. By combing ing standard polarization microscopy with video enhancement techniques it has been possible to image single filaments. In this case, however, filament intensity depends on the orientation of the polarizer and analyzer with respect to the specimen.

3-D reconstruction and analysis of mammalian mitotic spindle structure

1992 ◽  
Vol 50 (1) ◽  
pp. 578-579
Author(s):  
Kent McDonald ◽  
David Mastronarde ◽  
Rubai Ding ◽  
Eileen O'Toole ◽  
J. Richard McIntosh
Keyword(s):  
Cross Sections ◽  
Mitotic Spindle ◽  
Experimental Studies ◽  
Video Camera ◽  
Three Dimensions ◽  
Mitotic Spindles ◽  
Black And White ◽  
Reconstruction Methods ◽  
Spindle Structure ◽  
Tissue Culture Line

Mammalian spindles are generally large and may contain over a thousand microtubules (MTs). For this reason they are difficult to reconstruct in three dimensions and many researchers have chosen to study the smaller and simpler spindles of lower eukaryotes. Nevertheless, the mammalian spindle is used for many experimental studies and it would be useful to know its detailed structure.We have been using serial cross sections and computer reconstruction methods to analyze MT distributions in mitotic spindles of PtK cells, a mammalian tissue culture line. Images from EM negatives are digtized on a light box by a Dage MTI video camera containing a black and white Saticon tube. The signal is digitized by a Parallax 1280 graphics device in a MicroVax III computer. Microtubules are digitized at a magnification such that each is 10-12 pixels in diameter.

Laser Scanning Confocal Microscopy and Three-Dimesnsional Reconstruction of the Mitotic Spindles of Unequally Dividing Embryonic Cells

1990 ◽  
Vol 48 (3) ◽  
pp. 166-167
Author(s):  
J. Holy ◽  
G. Schatten
Keyword(s):  
Confocal Microscopy ◽  
Mitotic Spindle ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Confocal Microscopy ◽  
Two Dimensions ◽  
Embryonic Cells ◽  
Mitotic Spindles ◽  
Cleavage Division ◽  
Scanning Confocal Microscopy

One of the classic limitations of light microscopy has been the fact that three dimensional biological events could only be visualized in two dimensions. Recently, this shortcoming has been overcome by combining the technologies of laser scanning confocal microscopy (LSCM) and computer processing of microscopical data by volume rendering methods. We have employed these techniques to examine morphogenetic events characterizing early development of sea urchin embryos. Specifically, the fourth cleavage division was examined because it is at this point that the first morphological signs of cell differentiation appear, manifested in the production of macromeres and micromeres by unequally dividing vegetal blastomeres.The mitotic spindle within vegetal blastomeres undergoing unequal cleavage are highly polarized and develop specialized, flattened asters toward the micromere pole. In order to reconstruct the three-dimensional features of these spindles, both isolated spindles and intact, extracted embryos were fluorescently labeled with antibodies directed against either centrosomes or tubulin.

POPDC proteins and cardiac function

2019 ◽  
Vol 47 (5) ◽  
pp. 1393-1404 ◽  
Author(s):  
Thomas Brand
Keyword(s):  
Potential Role ◽  
Striated Muscle ◽  
Short Review ◽  
Effector Proteins ◽  
Muscle Disease ◽  
Disease Genes ◽  
Protein Protein Interaction ◽  
Interaction Partners ◽  
And Function

Abstract The Popeye domain-containing gene family encodes a novel class of cAMP effector proteins in striated muscle tissue. In this short review, we first introduce the protein family and discuss their structure and function with an emphasis on their role in cyclic AMP signalling. Another focus of this review is the recently discovered role of POPDC genes as striated muscle disease genes, which have been associated with cardiac arrhythmia and muscular dystrophy. The pathological phenotypes observed in patients will be compared with phenotypes present in null and knockin mutations in zebrafish and mouse. A number of protein–protein interaction partners have been discovered and the potential role of POPDC proteins to control the subcellular localization and function of these interacting proteins will be discussed. Finally, we outline several areas, where research is urgently needed.

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