Monensin blocks the first meiotic cell division of the Xenopus oocyte: Effect at the nuclear membrane level

1984 ◽  
Vol 9 (3) ◽  
pp. 339-349 ◽  
Author(s):  
J. Marot ◽  
J. Tso ◽  
D. Huchon ◽  
O. Mulner ◽  
R. Ozon
Keyword(s):  
Cell Division ◽  
Nuclear Membrane ◽  
Xenopus Oocyte ◽  
Meiotic Cell ◽  
Membrane Level

scholarly journals Control of the meiotic cell division program in plants

2013 ◽  
Vol 26 (3) ◽  
pp. 143-158 ◽  
Author(s):  
Erik Wijnker ◽  
Arp Schnittger
Keyword(s):  
Cell Division ◽  
Meiotic Cell

scholarly journals Effect of microinjection of a low-Mr human placenta protein tyrosine phosphatase on induction of meiotic cell division in Xenopus oocytes.

1990 ◽  
Vol 10 (2) ◽  
pp. 458-463 ◽  
Author(s):  
N K Tonks ◽  
M F Cicirelli ◽  
C D Diltz ◽  
E G Krebs ◽  
E H Fischer
Keyword(s):  
Cell Division ◽  
Insulin Receptor ◽  
Human Placenta ◽  
Protein Tyrosine Phosphatase ◽  
Xenopus Oocytes ◽  
Tyrosine Phosphatase ◽  
Meiotic Cell ◽  
Protein Tyrosine ◽  
Endogenous Activity ◽  
Maturation Promoting Factor

Homogeneous preparations of a protein phosphatase that is specific for phosphotyrosyl residues (protein tyrosine phosphatase [PTPase] 1B) were isolated from human placenta and microinjected into Xenopus oocytes. This resulted in an increase in activity of up to 10-fold over control levels, as measured in homogenates with use of an artificial substrate (reduced carboxamidomethylated and maleylated lysozyme). Microinjected PTPase was stable for at least 18 h. It is distributed within the oocyte in a manner similar to the endogenous activity and is suggestive of an interaction with cellular structures or molecules located predominantly in the animal hemisphere. The phosphatase markedly retarded (by up to 5 h) maturation induced by insulin. This, in conjunction with the demonstration that PTPase 1B abolished insulin stimulation of an S6 peptide (RRLSSLRA) kinase concomitant with a decrease in the phosphorylation of tyrosyl residues in a protein with the same apparent Mr as the beta subunit of the insulin and insulinlike growth factor 1 receptors (M. F. Cicirelli, N. K. Tonks, C. D. Diltz, E. H. Fischer, and E. G. Krebs, submitted for publication), provides further support for an essential role of protein tyrosine phosphorylation in insulin action. Furthermore, maturation was significantly retarded even when the PTPase was injected 2 to 4 h after exposure of the cells to insulin. PTPase 1B also retarded maturation induced by progesterone and maturation-promoting factor, which presumably do not act through the insulin receptor. These data point to a second site of action of the PTPase in the pathway of meiotic cell division, downstream of the insulin receptor and following the appearance of active maturation-promoting factor.

scholarly journals The Vaccinia-related Kinases Phosphorylate the N′ Terminus of BAF, Regulating Its Interaction with DNA and Its Retention in the Nucleus

2006 ◽  
Vol 17 (5) ◽  
pp. 2451-2464 ◽  
Author(s):  
R. Jeremy Nichols ◽  
Matthew S. Wiebe ◽  
Paula Traktman
Keyword(s):  
Drosophila Melanogaster ◽  
Cell Division ◽  
Nuclear Envelope ◽  
Temperature Sensitivity ◽  
Nuclear Membrane ◽  
Essential Role ◽  
Nuclear Architecture ◽  
Nuclear Chromatin ◽  
N Terminus ◽  
Protein Barrier

The vaccinia-related kinases (VRKs) comprise a branch of the casein kinase family whose members are characterized by homology to the vaccinia virus B1 kinase. The VRK orthologues encoded by Caenorhabditis elegans and Drosophila melanogaster play an essential role in cell division; however, substrates that mediate this role have yet to be elucidated. VRK1 can complement the temperature sensitivity of a vaccinia B1 mutant, implying that VRK1 and B1 have overlapping substrate specificity. Herein, we demonstrate that B1, VRK1, and VRK2 efficiently phosphorylate the extreme N′ terminus of the BAF protein (Barrier to Autointegration Factor). BAF binds to both DNA and LEM domain-containing proteins of the inner nuclear membrane; in lower eukaryotes, BAF has been shown to play an important role during the reassembly of the nuclear envelope at the end of mitosis. We demonstrate that phosphorylation of ser4 and/or thr2/thr3 abrogates the interaction of BAF with DNA and reduces its interaction with the LEM domain. Coexpression of VRK1 and GFP-BAF greatly diminishes the association of BAF with the nuclear chromatin/matrix and leads to its dispersal throughout the cell. Cumulatively, our data suggest that the VRKs may modulate the association of BAF with nuclear components and hence play a role in maintaining appropriate nuclear architecture.

scholarly journals Chromosomal Characteristics of NORs and Karyological Analysis of Tokay Gecko, Gekko gecko (Gekkonidae, Squamata) from Mitotic and Meiotic Cell Division

CYTOLOGIA ◽  
2014 ◽  
Vol 79 (3) ◽  
pp. 315-324 ◽  
Author(s):  
Isara Patawang ◽  
Alongklod Tanomtong ◽  
Sarun Jumrusthanasan ◽  
Wanpen Kakampuy ◽  
Lamyai Neeratanaphan ◽  
...  
Keyword(s):  
Cell Division ◽  
Meiotic Cell ◽  
Gekko Gecko ◽  
Karyological Analysis ◽  
Tokay Gecko

Effect of DCPA on Ultrastructure of Foxtail Millet Cells

Weed Science ◽  
1972 ◽  
Vol 20 (3) ◽  
pp. 220-225 ◽  
Author(s):  
C. T. Chang ◽  
Don Smith
Keyword(s):  
Electron Microscope ◽  
Cell Division ◽  
Cell Volume ◽  
Nuclear Membrane ◽  
Cell Walls ◽  
Foxtail Millet ◽  
Thylakoid Membranes ◽  
Setaria Italica ◽  
Advanced Stages ◽  
Giant Nuclei

Shoot apices of 7-day old foxtail millet(Setaria italica(L) Beauv.) seedlings treated with 2 and 20 mg/L of dimethyltetrachloroterephthalate (DCPA) were examined under the electron microscope. Cell division is interrupted. The nucleus and nucleolus do not disintegrate and chromosomes do not differentiate. Instead, giant nuclei and giant nucleoli occupy most of the cell volume in the meristematic regions. Several nucleolar caps form on the giant nucleolus; and in the advanced stages, they separate and are encircled by a nuclear membrane to form multiple nuclei. Other organelles are also affected. Cristae and thylakoid membranes of mitochondria and chloroplasts degenerate and multiple vacuoles form. Cell walls are markedly more osmophilic after DCPA treatment. Treated cells are less turgid than controls.

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