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Topic: Cleavage furrow


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In the News (Sun 24 Mar 19)

  
  Cleavage   (Site not responding. Last check: 2007-10-17)
Cleavage involves the division of the large amount of zygotic cytoplasm into numerous smaller cells while retaining the same zygotic size — in other words, the ratio of cytoplasm to nucleus decreases at a constant rate.
In all animals, cleavage stage division occurs at the fastest rate of cell division ever experienced in the lifetime of the animal; however, mammalian cleavage is among the slowest of all animals.
The different patterns of cleavage are classified by the amount and distribution of yolk in the egg and inherited patterns.
www-personal.umich.edu /~segelj/Cleavage.htm   (496 words)

  
 Center for Developmental Biology
Furrowing movements are based on force generated by an actin-myosin system called the contractile ring, which is constructed beneath the plasma membrane of the cleavage furrow and requires the activity of the small GTPase, Rho.
We found that in cultured cells, Rho begins to accumulate at the cell cortex in the cleavage plane before furrowing is appreciable and remains localized at the cleavage furrow throughout cytokinesis.
Interestingly, in astral microtubule-disrupted cells, Rho accumulation at the putative furrow position was detected only at areas where the central spindle microtubules were closely located to the cell cortex, suggesting that both astral and central microtubules have the ability to recruit Rho to the furrow, even within the same cell.
www.cdb.riken.go.jp /seminar/ext_10400.html   (353 words)

  
 Wadeson   (Site not responding. Last check: 2007-10-17)
Second cleavage occurs perpendicular to the first, and third cleavage is unequal, resulting in the formation of four large blastomeres that mark the future anterior of the developing embryo.
Cleavage is synchronous through 8th cleavage, originating at the apex of the animal pole and radiating out across the embryo.
Sixth cleavage continues to separate the inner blastoderm from the syncytial blastoderm and later correlates with the boundary of the cellular blastoderm that forms as cell movements begin.
www.mbl.edu /BiologicalBulletin/VIDEO/wadeson/index.html   (276 words)

  
 ZFIN Cleavage Stages   (Site not responding. Last check: 2007-10-17)
The furrow arises near the animal pole and progresses rapidly towards the vegetal pole, passing through only the blastodisc and not the yolky region of the egg (Fig.
Their complete cleavage occurs near the end of the 16-cell stage because of the way the cleavage furrows undercut the blastodisc from the center, going outwards towards the blastodisc margin.
During the same cleavage the horizontal divisions of marginal blastomeres present at cycle 6 produce two EVL sister cells, and in a face view of the 64-cell stage one sees three tiers of EVL cells (Fig.
www.grs.nig.ac.jp:6070 /zf_info/zfbook/stages/cleave_stgs.html   (812 words)

  
 The last stage is TELOPHASE   (Site not responding. Last check: 2007-10-17)
At the start of telophase a cleavage furrow begins to form at the cells "equator" or center, almost like a string tightening around a balloon.
The cleavage furrow is a "squeezing in" of the cell membrane and it will eventually "cut" the cell in half.
In the later part of telophase, the claevage furrow contracts toward the center of the cell and the "cells in motion" creates two new independent cells.
library.thinkquest.org /J0110742/Mitosis/4.htm   (71 words)

  
 Cleavage
Thus, blastomere volume is decreased during cleavage to produce the small, individual cellular units that participate in the subsequent morphogenic events that mold the embryo.
At the end of cleavage, the somatic cell cycle is established.
This structure was found at the leading edge of all cleavage furrows until the mid-blastula stage.
www.acs.ucalgary.ca /~browder/cleavage.html   (623 words)

  
 Pharyngula::Polarity in the mammalian egg
Mammalian ova lack any overt asymmetries, and their early cleavages are simple and equal, producing a clump of cells called a morula with no discernible up, down, left, right, back, or front.
Cleavage furrow is formed at the overlap of extended microtubules (arrowheads).
Hiiragi T, Solter D (2004) First cleavage plane of the mouse egg is not predetermined but defined by the topology of the two apposing pronuclei.
pharyngula.org /index/weblog/comments/polarity_in_the_mammalian_egg   (835 words)

  
 Feb 17 Lecture Outline
Because of the concentration of yolk in the vegetal hemisphere the formation of the cleavage furrow in the yolk-containing ventral portion is slower and lags behind that in the animal hemisphere.
Cleavage occurs at oblique angles with daughter cells either moving to the right or to the left.
Cleavage in mammalian embryos is rotational, holoblastic, and asynchronous.
departments.oxy.edu /biology/linden/bio220/feb17.html   (655 words)

  
 Cleavage
There are two major consequences of cleavage: production of a multicellular organism from a single-celled zygote and acquisition by individual cells or groups of cells of differences that will facilitate their later development into different cell types.
Cleavage also increases the number of nuclei, which amplifies the number of templates that will facilitate the later production of specialized proteins needed for formation of a functional organism.
They hypothesize that the role of this structure is to recruit membrane vesicles to the furrow's leading edge for new membrane assembly.
www.ucalgary.ca /UofC/eduweb/virtualembryo/cleavage.html   (595 words)

  
 The Cytokinetic Mafia: Mafia Members at ASCB 1999
We are now determining whether the interaction between anillin and myosin is important for the assembly of the cleavage furrow and whether this interaction is regulated during the transition from mitosis to interphase.
We suggest that spindle midzone microtubules are necessary for vesicle targeting to the late cleavage furrow in a manner analogous to the function of the phragmoplast microtubules of plant cell cytokinesis.
Cleavage furrows could not be induced, however, in manipulated prophase or aphidocolin-arrested blastomeres, suggesting that the mere presence of asters is not sufficient to induce the spindle poles and the surface in manipulated blastomeres will further decrease the timing between anaphase onset and cleavage.
www.bio.unc.edu /faculty/salmon/lab/mafia/mafiaascb1999.html   (2554 words)

  
 BioMed Central | Full text | Quantitation of the distribution and flux of myosin-II during cytokinesis
To relate the amount of cleavage furrow myosin-II to the potential forces that might be generated by the cleavage furrow cortex, we estimated the minimal force requirements for cell cleavage using the simple mathematical relationship proposed by Yoneda and Dan [4].
Four regions of dividing cells were defined for analysis purposes: the cortex as a whole, the cytoplasm, the cortex underlying the cleavage furrow and the cortex underlying the poles (Figure 1).
The cortex underlying the furrow is considered to extend outwards from the equator as far as the point of inflection of the curvature of the cell (Figure 1).
www.biomedcentral.com /1471-2121/3/4   (7566 words)

  
 Cytokinesis
Mid-body forms as the cleavage furrow narrows further, the chromosomes de-condense and the nuclear envelope reforms.
The position of the cleavage furrow is determined by anti-parallel microtubule arrays (usually the spindle).
The cleavage furrow is composed primarily of actin arranged as concentric anti-parallel filaments.
www.bms.ed.ac.uk /research/others/smaciver/lectures/CS6.htm   (1464 words)

  
 ZFIN Cleavage Stages
The furrow arises near the animal pole and progresses rapidly towards the vegetal pole, passing through only the blastodisc and not the yolky region of the egg (Fig.
Their complete cleavage occurs near the end of the 16-cell stage because of the way the cleavage furrows undercut the blastodisc from the center, going outwards towards the blastodisc margin.
During the same cleavage the horizontal divisions of marginal blastomeres present at cycle 6 produce two EVL sister cells, and in a face view of the 64-cell stage one sees three tiers of EVL cells (Fig.
zfin.org /zf_info/zfbook/stages/cleave_stgs.html   (812 words)

  
 Int. J. Dev. Biol. - Altering the position of the first horizontal cleavage furrow of the amphibian (Xenopus) egg ...
Altering the position of the first horizontal cleavage furrow of the amphibian (Xenopus) egg reduces embryonic survival.
ABSTRACT The animal/vegetal cleavage ratio (AVCR), defined as the ratio of the height of the animal blastomere to the height of the Xenopus embryo at the 8 cell stage, can be shifted by placing embryos in novel gravitational fields: clinostating (microgravity simulation) increases AVCR, and centrifugation (hypergravity simulation) reduces AVCR.
Based on the additive or antagonistic effects of combined treatments, it is postulated that the primary cause of AVCR changes is an alteration in the distribution of yolk platelets and the rearrangement of microtubule arrays.
www.ijdb.ehu.es /web/paper.php?doi=1295563   (231 words)

  
 Welcome to the Spang lab
A cell needs to replicate the DNA, divide it equally between two poles during mitosis and finally the cleavage furrow separates mother and daughter cell giving raise to 2 cells.
We focus on the transport of membranes into the division plane and the insertion into the ingressing cleavage furrow.
So far we succeeded in identifying some genes, that are currently under investigation in our lab.
www.fml.tuebingen.mpg.de /spang/worms.htm   (148 words)

  
 BioInteractive's Animation Console
Note that the formation of the cleavage furrow in the upper cell, which normally pinches off and divides the cell in two, is frozen at the instant of furrowstatin addition.
After furrowstatin is washed away, represented by the removal of the blue tint, the cleavage furrow forms and the cell divides.
This structure is known as the cleavage furrow.
www.hhmi.org /biointeractive/animations/furrowstatin/furrow_print.htm   (679 words)

  
 Marine Biological Laboratory
That study revealed that following second cleavage MAPK expression was present in the two posterior blastomeres and with third cleavage, MAPK became localized within the two posterior mid-line macromeres flanking the first cleavage furrow.
Inhibition of first cleavage resulted in equalization of third cleavage and loss or reduction of MAPK expression in the posterior mid-line blastomeres in those embryos.
These results link first cleavage, MAPK and the D lineage in cephalopods and support the notion that squid possess mirror image A, B, C, and D quadrants organized along their first cleavage furrow as described in the Cephalopoda by Adolf Naef (1928).
www.mbl.edu /gsm/abstracts06/abstract_crawford.html   (314 words)

  
 Cell Research, 15(11-12), Nov-Dec 2005
By laser scanning fluorescence microscopy for quantitative measurement of fluorescence intensity changes on egg surface stained with fluoresein isothiocyanate during cleavage furrow extending forward, it was found that in area of presumptive cleavage furrow the scanning curve became V shape, indicating dark stripe appeared in that place.
During the distance between two borders of M shape increasing from 50 um to 100um, a fluorescence peak came to sight in the middle or the M shape, which being the cleavge furrow bottom.
By the sides of cleavage furrow the stress folds became cospicous after double stripe stage, showing the stretching of the egg surface being increased.
www.cell-research.com /19951/951-02.htm   (229 words)

  
 Cleavage Furrow
he cleavage furrow is an actin rich "purse string" that draws tight to separate daughter cells to complete cytokinesis in cell division.
The main function of myosin II is to contract within the the formed cleavage furrow to steadily reduce its diameter as the spindle recedes towards the poles.
Schroeder, T.E. Cytokinesis: filaments in the cleavage furrow.
www.bms.ed.ac.uk /research/others/smaciver/Cyto-Topics/cleavage_furrow.htm   (5229 words)

  
 Rappaport rules: Cleavage furrow induction inĀ animalĀ cells -- Oegema and Mitchison 94 (10): 4817 -- Proceedings of ...
the spindle midzone and the cortex to inhibit furrowing in flattened
The third model for cleavage furrow positioning is equatorial stimulation by signals from the spindle midzone.
actin to be enriched in the Rappaport furrow.
www.pnas.org /cgi/content/full/94/10/4817   (3068 words)

  
 Interactive Fly, Drosophila
In wild-type cells, anillin accumulates at the cleavage furrow at the onset of anaphase and is restricted to the contractile ring during anaphase and telophase.
Pnut, a member of the septin family of proteins, accumulates at the cleavage furrow in late anaphase and is associated with the contractile ring during telophase.
In wild-type neuroblasts, the cleavage furrow coincides with the border of the Pon-GFP crescent at cytokinesis, therefore the GFP signal is distributed all around the GMC cell membrane as soon as the GMC is formed.
www.sdbonline.org /fly/cytoskel/pebble4.htm   (9857 words)

  
 Chapter 13B. Fertilization and Cleavage   (Site not responding. Last check: 2007-10-17)
Cleavage is a series of rapid cell divisions without cell growth or gene expression which occurs in early embryogenesis.
In the very yolky eggs of fish and birds, the cleavage furrow is slowed, or even blocked, by the presence of the yolk.
Cleavage in the zebrafish embryo is limited to a small region on "top" of the yolky mass.
www2.kenyon.edu /Depts/BioEllipse/courses/biol114/Chap13/Chapter_13B.html   (1840 words)

  
 Nir2, a Human Homolog of Drosophila melanogaster Retinal Degeneration B Protein, Is Essential for Cytokinesis -- Litvak ...
is recruited to the cleavage furrow and the midbody during cytokinesis.
The localization of Nir2 at the cleavage furrow in anaphase (c and e) and to the midbody during telophase (g) is indicated by an arrow.
at the cleavage furrow and of the plasma membrane.
mcb.asm.org /cgi/content/full/22/14/5064   (5902 words)

  
 [No title]
The cooperation of myosin II and cortexillin I in determining the position of a cleavage furrow is subject of the paper.
If asymmetric cleavage in the absence of myosin II partitions a cell into a binucleate and an anucleate portion, cell-surface ruffles are induced along the cleavage furrow, which lead to movement of the anucleate portion along the connecting strand towards the binucleate one.
Conclusions: In myosin II-null cells, cleavage furrow positioning occurs in two steps: priming of the furrow region and actual cleavage, which may proceed in the middle or at one border of the cortexillin ring.
www.dictybase.org /newsletter/Vol_14(2000)/Dicty-News.v14.%2310.txt   (719 words)

  
 Sullivan Lab Research - Cytokinesis
He found that it is in a complex with Spectrin and CLIP-170 and is required for vesicle-mediated delivery to the leading edge of the invaginating cellularization furrows.
Rab11, a member of the Rab family of small GTPases involved in vesicle targeting, is a well established marker of the RE and is required for recycling endosome organization and function.
We are currently in the final stages of a study demonstrating that the cell-cycle regulated location of Nuf at the recycling endosome relies on a physical association with Dynein.
bio.research.ucsc.edu /people/sullivan/cytokinesis.html   (820 words)

  
 AN ATLAS OF XENOPUS EMBRYOGENESIS   (Site not responding. Last check: 2007-10-17)
The cleavage furrow is created by the animal plasma membrane and the adjacent cortex.
The larger vesicle in the furrow is the blastocoel anlage.
The vesicles at the tip of the furrow have a primary role in the formation of the plasma membrane.
www.bioscience.org /atlases/embryoge/htm/large11.htm   (43 words)

  
 OHSU School of Dentistry - Integrative Biosciences
In animal cells undergoing cytokinesis, cleavage furrowing haslong been recognized to be a microfilament-dependent process.
Recently, we discovered a novel structure in the cleavage furrows of eggs of the frog Xenopus laevis, consisting of numerous bundles of radially arranged, acetylated microtubules emanating from the vicinity of the contractile ring.
Since all receptor-mediated, cell-cell interactions between the blastomeres of the early embryo depend on the composition of these basolateral surfaces, the mechanism of their formation is of great interest to developmental biologists; thus, we are presently examining the microtubule dependence of exocytosis of basolaterally targetted vesicles in the cleavage furrow.
www.ohsu.edu /academic/sod/ib/acad_staff/danilchi.htm   (255 words)

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