Talk:Cell Division - Mitosis
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Cite this page: Hill, M.A. (2026, October 5) Embryology Cell Division - Mitosis. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Cell_Division_-_Mitosis |
2012
The nucleoporin ELYS/Mel28 regulates nuclear envelope subdomain formation in HeLa cells
Nucleus. 2012 Mar 1;3(2). [Epub ahead of print]
Clever M, Funakoshi T, Mimura Y, Takagi M, Imamoto N. Source Cellular Dynamics Laboratory; Riken Advanced Science Institute; Saitama, Japan.
Abstract
In open mitosis, the nuclear envelope (NE) reassembles at the end of each mitosis. This process involves the reformation of the nuclear pore complex (NPC), the inner and outer nuclear membranes, and the nuclear lamina. In human cells, cell cycle-dependent NE subdomains exist, characterized as A-type lamin-rich/NPC-free or B-type lamin-rich/NPC-rich, which are initially formed as core or noncore regions on mitotic chromosomes, respectively. Although postmitotic NE formation has been extensively studied, little is known about the coordination of NPC and NE assembly. Here, we report that the nucleoporin ELYS/Mel28, which is crucial for postmitotic NPC formation, is essential for recruiting the lamin B receptor (LBR) to the chromosomal noncore region. Furthermore, ELYS/Mel28 is responsible for focusing of A-type lamin-binding proteins like emerin, Lap2α and the barrier-to-autointegration factor (BAF) at the chromosomal core region. ELYS/Mel28 biochemically interacts with the LBR in a phosphorylation-dependent manner. Recruitment of the LBR depends on the nucleoporin Nup107, which interacts with ELYS/Mel28, but not on nucleoporin Pom121, suggesting that the specific molecular interactions with ELYS/Mel28 are involved in the NE assembly at the noncore region. The depletion of the LBR affected neither the behavior of emerin nor Lap2α indicating that the recruitment of the LBR to mitotic chromosomes is not involved in formation of the core region. The depletion of ELYS/Mel28 also accelerates the entry into cytokinesis after recruitment of emerin to chromosomes. Our data show, that ELYS/Mel28 plays a role in NE subdomain formation in late mitosis.
PMID 22555603
The Abbreviated Pluripotent Cell Cycle
J Cell Physiol. 2012 May 2. doi: 10.1002/jcp.24104. [Epub ahead of print]
Kapinas K, Grandy R, Ghule P, Medina R, Becker K, Pardee A, Zaidi SK, Lian J, Stein J, van Wijnen A, Stein G. Source Department of Cell Biology, University of Massachusetts Medical School, Worcester, MA 01655.
Abstract
Human embryonic stem cells and induced pluripotent stem cells proliferate rapidly and divide symmetrically producing equivalent progeny cells. In contrast, lineage committed cells acquire an extended symmetrical cell cycle. Self-renewal of tissue-specific stem cells is sustained by asymmetric cell division where one progeny cell remains a progenitor while the partner progeny cell exits the cell cycle and differentiates. There are three principal contexts for considering the operation and regulation of the pluripotent cell cycle: temporal, regulatory andstructural. The primary temporal context that the pluripotent self-renewal cell cycle of human embryonic stem cells (hESCs) is a short G1 period without reducing periods of time allocated to S phase, G2, and mitosis. The rules that govern proliferation in hESCs remain to be comprehensively established. However, several lines of evidence suggest a key role for the naïve transcriptome of hESCs, which is competent to stringently regulate the ESC cell cycle. This supports the requirements of pluripotent cells to self propagate while suppressing expression of genes that confer lineage commitment and/or tissue specificity. However, for the first time, we consider unique dimensions to the architectural organization and assembly of regulatory machinery for gene expression in nuclear microenviornments that define parameters of pluripotency. From both fundamental biological and clinical perspectives, understanding control of the abbreviated embryonic stem cell cycle can provide options to coordinate control of proliferation versus differentiation. Wound healing, tissue engineering, and cell-based therapy to mitigate developmental aberrations illustrate applications that benefit from knowledge of the biology of the pluripotent cell cycle. J. Cell. Physiol. © 2012 Wiley Periodicals, Inc. Copyright © 2012 Wiley Periodicals, Inc.
PMID 22552993
Bipolar metaphase spindle formation in a fucoid alga cell. Normal spindle formation is disrupted by treatment with the Kinesin-5 inhibitor monastrol. Treated zygotes arrest at the spindle assembly check point and produce monasters, multipolar spindles, and numerous cytasters. Spindle microtubules are shown in green and condensed chromatin is shown in red. This month features a guest image which was recently published in BMC Plant Biology.
http://www.biomedcentral.com/bmccellbiol/imageofthemonth/archive/2006/10
Deciphering protein function during mitosis in PtK cells using RNAi
Knockdown of the kinesin Eg5 leads to mitotic defects. Knockdown of Eg5 levels by treatment with siRNA results in cells with monopolar spindles and a mitotic delay (right hand cell). Microtubule staining is shown in green, Eg5 in red and DNA in blue.
