Recognition-alignment and adhesion in myoblast fusion

1995 ◽  
Vol 53 ◽  
pp. 900-901
Author(s):  
R. González Santander ◽  
M.V. Toledo Lobo ◽  
F.J. Martínez Alonso ◽  
G. Martínez Cuadrado ◽  
M González-Santander Martínez ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Chick Embryo ◽  
Membrane Fusion ◽  
Basal Lamina ◽  
Neural Tube ◽  
Myoblast Fusion ◽  
Lateral Region ◽  
Blast Cells ◽  
Conventional Methods

Myoblast fusion results from a sequence of different stages, previously demonstrated “in vitro”. After withdrawal from the cell cycle, myoblasts align forming long chains, in a process termed “recognition-alignment”. This stage is extracellular Ca2+ and N-Cadherin dependent. Alignment is followed by adhesion, defined as the stage prior to membrane fusion when aggegates are resistant to dispersal by EDTA. Adhesion is extracellular Ca2+-independent and N-CAM-dependent. Membrane fusion originates multinucleate myotubes.We have studied these stages of myoblast fusion at the brachial myotome of chick embryo from 51 to 105 h. of incubation. Samples were obtained by embryo microdissection and included the neural tube, the notochord and the brachial somites. These samples were embedded in araldite by conventional methods. Some samples were embedded in Unicryl, a recently formulated GMA derived resin.The first myoblasts clusters were observed in the ventral-lateral region of the brachial myotome in 22-24 Hamburger and Hamilton stages embryos. Clusters of pre-fusion myoblasts are usually surrounded by “electrondense blast cells” within a basal lamina in process of formation.

Cesium ions delay membrane fusion of chick embryo myoblasts in vitro: a conductivity study

1988 ◽  
Vol 945 (1) ◽  
pp. 56-64 ◽  
Author(s):  
Maria T. Santini ◽  
Adalberto Bonincontro ◽  
Cesare Cametti ◽  
Pietro L. Indovina
Keyword(s):  
Chick Embryo ◽  
Membrane Fusion ◽  
Cesium Ions

Effect of the notochord on proliferation and differentiation in the neural tube of the chick embryo

Development ◽  
1989 ◽  
Vol 107 (4) ◽  
pp. 793-803 ◽  
Author(s):  
H.W. van Straaten ◽  
J.W. Hekking ◽  
J.P. Beursgens ◽  
E. Terwindt-Rouwenhorst ◽  
J. Drukker
Keyword(s):  
Cell Cycle ◽  
Chick Embryo ◽  
Mitotic Index ◽  
Neural Tube ◽  
Control Area ◽  
Basal Plate ◽  
The Third ◽  
Proliferation And Differentiation ◽  
Neural Tube Development ◽  
Number Of Cells

After implantation of a notochord fragment lateral to the neural tube in a 2-day chick embryo, at 4 days the ipsilateral neural tube half was increased in size and axons left the neural tube in a broad dorsoventral area (van Straaten et al. 1985). This enlargement appears to coincide with an increased area of AChE-positive basal plate neuroblasts, as determined with scan-cytophotometry. The effect was ipsilateral and local: clear effects were seen only when the implant was localized less than 80 microns from the neural tube and over 120 microns from the ventral notochord. In order to investigate the expected enhancement of proliferation, the mitotic density and the number of cells at the site of the implant at 3 days was determined and the mitotic index calculated. All three parameters showed an increase. It was concluded that the cell cycle was shorter in the implant area relative to the control area, at least during the third day. At 4 days the number of cells was still increased, predominantly in the basal plate. It appeared that the numerical increase was for the larger part due to neuroblasts. The synergism of two notochords thus resulted in enhancement of proliferation and differentiation in the neural tube. It is suggested that the notochord merely regulates and arranges the surrounding sclerenchymal cells, which are the effective cells in the regulation of neural tube development.

Subcellular and Cell-Cycle Expression Profiles of CDK-Inhibitors in Normal Differentiating Myeloid Cells

Blood ◽  
1999 ◽  
Vol 93 (9) ◽  
pp. 2907-2917 ◽  
Author(s):  
B. Yaroslavskiy ◽  
S. Watkins ◽  
A.D. Donnenberg ◽  
T.J. Patton ◽  
R.A. Steinman
Keyword(s):  
Cell Cycle ◽  
Cellular Proliferation ◽  
Expression Profiles ◽  
Behavior Changes ◽  
Cdk Inhibitors ◽  
In Vitro Differentiation ◽  
Cd34 Cells ◽  
Blast Cells ◽  
Cell Cycle Inhibitors

A central question in hematopoiesis is how cell-cycling behavior changes during the emergence of the differentiated state. To further understand what genetic regulators might couple proliferation status to differentiation, we studied the expression of the cell-cycle inhibitors p21 and p27 during the in vitro differentiation of normal CD34+ blast cells along the myeloid lineage. We find p27 but not p21 to be expressed in freshly harvested resting CD34+ cells. Thereafter, p21 levels peak concurrent with cellular proliferation and then decline in expression as cells undergo terminal differentiation. In contrast, p27 levels are fairly constant but the subcellular localization of p27 changes from nuclear expression to predominantly cytoplasmic expression and finally to perinuclear localization at progressive stages of differentiation. This report discusses the implications of these findings.

scholarly journals Flow cytometric evaluation of cell cycle characteristics during in vitro differentiation of chick embryo chondrocytes

Cytometry ◽  
1988 ◽  
Vol 9 (4) ◽  
pp. 281-290 ◽  
Author(s):  
W. Giaretti ◽  
S. Bruno ◽  
A. DiVinci ◽  
E. Geido ◽  
G. Moro ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Chick Embryo ◽  
In Vitro Differentiation ◽  
Flow Cytometric ◽  
Flow Cytometric Evaluation

Cytochemical localization of calcium in myoblasts of the chick embryo myotome

1995 ◽  
Vol 53 ◽  
pp. 1062-1063
Author(s):  
R. González Santander ◽  
M.V. Toledo Lobo ◽  
F.J. Martínez Alonso ◽  
G. Martínez Cuadrado ◽  
M. Gánzalez-Santander Martinez ◽  
...  
Keyword(s):  
Membrane Fusion ◽  
Muscle Development ◽  
Myoblast Fusion ◽  
Cytochemical Localization ◽  
Intracellular Ca ◽  
First Time ◽  
And Storage ◽  
Multinucleated Myotubes

Muscle fibers are derived from multinucleated myotubes which are themselves formed during embryonic development by the fusion of mononucleated myoblasts. Myoblast fusion results from a sequence of different and highly orchestrated stages demonstrated previously in vitro: recognitionalignment, adhesion and membrane fusion. Like many other fusion systems, myoblast fusion is Ca2+ - dependent. The role of Ca2+ is multiple since it is needed for muscle cell differentiation, for the alignment stage and it has also been demonstrated that Ca2+ influx precedes fusion increasing free intracellular Ca2+. It has been proposed that this increase in free intracellular Ca2+ may activate an enzimatic cascade which leads to membrane fusion.The present study, using the K-pyroantimonate method, describes Ca2+ localization and storage in myoblasts before fusion for the first time, since this method had not been applied to skeletal muscle development studies before. Chick embryos from 51 to 108 h. of incubation (Hamburger and Hamilton stages 16 to 25) were used.

Subcellular and Cell-Cycle Expression Profiles of CDK-Inhibitors in Normal Differentiating Myeloid Cells

Blood ◽  
1999 ◽  
Vol 93 (9) ◽  
pp. 2907-2917 ◽  
Author(s):  
B. Yaroslavskiy ◽  
S. Watkins ◽  
A.D. Donnenberg ◽  
T.J. Patton ◽  
R.A. Steinman
Keyword(s):  
Cell Cycle ◽  
Cellular Proliferation ◽  
Expression Profiles ◽  
Behavior Changes ◽  
Cdk Inhibitors ◽  
In Vitro Differentiation ◽  
Cd34 Cells ◽  
Blast Cells ◽  
Cell Cycle Inhibitors

Abstract A central question in hematopoiesis is how cell-cycling behavior changes during the emergence of the differentiated state. To further understand what genetic regulators might couple proliferation status to differentiation, we studied the expression of the cell-cycle inhibitors p21 and p27 during the in vitro differentiation of normal CD34+ blast cells along the myeloid lineage. We find p27 but not p21 to be expressed in freshly harvested resting CD34+ cells. Thereafter, p21 levels peak concurrent with cellular proliferation and then decline in expression as cells undergo terminal differentiation. In contrast, p27 levels are fairly constant but the subcellular localization of p27 changes from nuclear expression to predominantly cytoplasmic expression and finally to perinuclear localization at progressive stages of differentiation. This report discusses the implications of these findings.

In vivo and in vitro studies on the hypoblast and definitive endoblast of avian embryos

Development ◽  
1978 ◽  
Vol 46 (1) ◽  
pp. 187-205
Author(s):  
E. J. Sanders ◽  
Ruth Bellairs ◽  
P. A. Portch
Keyword(s):  
Chick Embryo ◽  
Basal Lamina ◽  
Contact Inhibition ◽  
In Vitro Studies ◽  
Hanging Drop ◽  
Avian Embryos ◽  
Sem And Tem ◽  
Consistent Manner

An unusual example of the invasion of one tissue by another occurs during gastrulation in the chick embryo when the definitive endoblast becomes inserted into the hypoblast. The two tissues were examined morphologically by SEM and TEM. They resemble each other in being of an epithelial type, though neither possesses a basal lamina. The definitive endoblast cells are flatter than the hypoblast cells and more closely attached to one another. When they were explanted in hanging drop cultures, the two tissues were found to exhibit differences in their behaviour. In comparison with the definitive endoblast, the hypoblast cells attached more readily to the glass, produced larger ruffle membranes, moved more rapidly, showed poorer contact-inhibition of locomotion and showed a greater tendency to break away from the main explant. When a hypoblast explant was confronted with a definitive endoblast explant, the hypoblast cells became displaced by the definitive endoblast. The hypoblast explant tended to fragment into smaller groups of cells, many of which migrated around the definitive endoblast, thus mimicking the situation in vivo. Control experiments comprised confronting hypoblast with hypoblast, hypoblast with somites, definitive endoblast with definitive doblast, and definitive endoblast with somites. The hypoblast explants behaved in a consistent manner, always fragmenting when coming into contact with cells from a confronting xplant. The definitive endoblast explants showed more contact inhibition of locomotion when confronted with definitive endoblast or with somites than when confronted with hypoblast. It is suggested therefore that the ability of the hypoblast cells to separate from one another may play an important role in the penetration of the hypoblast by the definitive endoblast both in vitro and in vivo.

scholarly journals Changes in the surface membrane during myoblast fusion

1980 ◽  
Vol 190 (3) ◽  
pp. 647-652 ◽  
Author(s):  
D H Curtis ◽  
K J Micklem ◽  
K Gill ◽  
C A Pasternak
Keyword(s):  
Amino Acids ◽  
Chick Embryo ◽  
Surface Membrane ◽  
Surface Protein ◽  
Myoblast Fusion ◽  
The Other ◽  
Methyl Glucoside ◽  
Simple Diffusion ◽  
Approximate Doubling

1. During fusion of chick-embryo myoblasts in culture, the surface membrane is affected as follows. Uptake of 2-aminoisobutyrate and 2-deoxyglucose, each of which is concentrated 20-fold relative to its concentration in the medium, is unaltered; uptake of alpha-methyl glucoside and choline (15 mM), each of which equilibrates relative to its concentration in the medium, approximately doubles. An approximate doubling also occurs in iodinatable surface protein (and in total protein) and in cell surface area as judged by light-microscopy. Adenylate cyclase (in the absence or the presence of fluoride) increases by more than 2-fold. 2. It is concluded that, during myoblast fusion cells increase in size, and this is reflected in an increased rate of simple diffusion; the rate of facilitated processes such as the uptake of amino acids and sugars, on the other hand, remains unaltered, though the activity of certain enzymes is increased. These results indicate that specific changes in the function of surface membrane occur during myoblast fusion in vitro.

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