scholarly journals A cell lineage analysis of segmentation in the chick embryo

Development ◽  
1988 ◽  
Vol 104 (Supplement) ◽  
pp. 231-244 ◽  
Author(s):  
Claudio D. Stern ◽  
Scott E. Fraser ◽  
Roger J. Keynes ◽  
Dennis R. N. Primmett
Keyword(s):  
Cell Division ◽  
Chick Embryo ◽  
Neural Tube ◽  
Single Cells ◽  
Cell Lineage ◽  
Subsequent Development ◽  
Ventral Horn ◽  
Cell Division Cycle ◽  
Lateral Plate ◽  
Somite Formation

We have studied the lineage history of the progenitors of the somite mesoderm and of the neural tube in the chick embryo by injecting single cells with the fluorescent tracer, rhodamine-lysine-dextran. We find that, although single cells within the segmental plate give rise to discrete clones in the somites to which they contribute, neither the somites nor their component parts (sclerotome, dermatome, myotome or their rostral and caudal halves) are `compartments' in the sense defined in insects. Cells in the rostral two thirds or so of the segmental plate contribute only to somite tissue and divide about every 10 h, while those in the caudal portions of this structure contribute both to the somites and to intermediate and lateral plate mesoderm derivatives. In the neural tube, the descendants of individual prospective ventral horn cells remain together within the horn, with a cycle time of 10 h. We have also investigated the role of the cell division cycle in the formation and subsequent development of somites. A single treatment of 2-day chick embryos with heat shock or a variety of drugs that affect the cell cycle all produce repeated anomalies in the pattern of somites and vertebrae that develop subsequent to the treatment. The interval between anomalies is 6-7 somites (or a multiple of this distance), which corresponds to 10 h. This interval is identical to that measured for the cell division cycle. Given that cell division synchrony is seen in the presomitic mesoderm, we suggest that the cell division cycle plays a role in somite formation. Finally, we consider the mechanisms responsible for regionalization of derivatives of the somite, and conclude that it is likely that both cell interactions and cell lineage history are important in the determination of cell fates.

Periodic segmental anomalies induced by heat shock in the chick embryo are associated with the cell cycle

Development ◽  
1989 ◽  
Vol 105 (1) ◽  
pp. 119-130 ◽  
Author(s):  
D.R. Primmett ◽  
W.E. Norris ◽  
G.J. Carlson ◽  
R.J. Keynes ◽  
C.D. Stern
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Heat Shock ◽  
Simple Model ◽  
Chick Embryo ◽  
Heat Shock Proteins ◽  
Cell Division Cycle ◽  
The Other ◽  
Chick Embryos ◽  
Shock Proteins

This study provides evidence that cells destined to segment together into somites have a degree of cell division synchrony. We have measured the duration of the cell division cycle in somite and segmental plate cells of the chick embryo as 9.5 h using [3H]thymidine pulse- and-chase. Treatment of embryos with any of a variety of inhibitors known to affect the cell division cycle causes discrete periodic segmental anomalies: these anomalies appear about 6–7 somites after treatment and, in some cases, a second anomaly is observed 6 to 7 somites after the first. Since somites take 1.5 h to form, the 6- to 7- somite interval corresponds to about 9–10 h, which is the duration of the cell cycle as determined in these experiments. The anomalies are similar to those seen after heat shock of 2-day chick embryos. Heat shock and some of the other treatments induce the expression of heat-shock proteins (hsp); however, since neither the expression nor the distribution of these proteins relate to the presence or distribution of anomalies seen, we conclude that hsps are not responsible for the pattern of segmental anomalies observed. The production of periodic segmental anomalies appears to be linked to the cell cycle. A simple model is proposed, in which we suggest that the cell division cycle is involved directly in gating cells that will segment together.

The distribution of endogenous retinoic acid in the chick embryo: implications for developmental mechanisms

Development ◽  
1998 ◽  
Vol 125 (21) ◽  
pp. 4133-4144 ◽  
Author(s):  
M. Maden ◽  
E. Sonneveld ◽  
P.T. van der Saag ◽  
E. Gale
Keyword(s):  
Retinoic Acid ◽  
Chick Embryo ◽  
Neural Tube ◽  
Cell System ◽  
Limb Bud ◽  
Lateral Plate ◽  
F9 Cells ◽  
Chick Embryogenesis ◽  
Wide Range ◽  
Very High

The aim of these experiments was to determine the endogenous distribution of retinoic acid (RA) across a wide range of embryonic stages in the chick embryo. By high pressure liquid chromatography, it was revealed that didehydroRA is the most prevalent retinoic acid in the chick embryo and that the tissues of the stage 24 embryo differed widely in their total RA content (didehydroRA + all-trans-RA). Some tissues such as the heart had very little RA and some such as the neural tube had very high levels, the total variation between these two being 29-fold. We showed that these tissues also synthesised RA and released it into the medium, thus validating the use of the F9 reporter cell system for further analyses of younger staged embryos. With these F9 cells, we showed that, at stage 4, the posterior end of the embryo had barely detectably higher levels of RA than the anterior end, but that a significant level of RA generation was detected as soon as somitogenesis began. Then a sharp on/off boundary of RA was present at the level of the first somite. We could find no evidence for a posterior-to-anterior gradient of RA. Throughout further development, various consistent observations were made: the developing brain did not generate RA, but the spinal part of the neural tube generated it at very high levels so there must be a sharp on/off boundary in the region of the hindbrain/spinal cord junction; the mesenchyme surrounding the hindbrain generated RA whereas the hindbrain itself did not; there was a variation in RA levels from the midline outwards with the highest levels of RA in the spinal neural tube followed by lower levels in the somites followed by lower levels in the lateral plate; the posterior half of the limb bud generated higher levels than the anterior half. With these observations, we were able to draw maps of endogenous RA throughout these early stages of chick embryogenesis and the developmental implications of these results are discussed.

Initial steps of myogenesis in somites are independent of influence from axial structures

Development ◽  
1994 ◽  
Vol 120 (11) ◽  
pp. 3073-3082 ◽  
Author(s):  
E. Bober ◽  
B. Brand-Saberi ◽  
C. Ebensperger ◽  
J. Wilting ◽  
R. Balling ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Neural Tube ◽  
Cell Lineage ◽  
Subsequent Development ◽  
Paraxial Mesoderm ◽  
Surgical Removal ◽  
Axial Muscles ◽  
Muscle Formation ◽  
Vertebrate Embryos ◽  
Myotomal Muscle

Formation of paraxial muscles in vertebrate embryos depends upon interactions between early somites and the neural tube and notochord. Removal of both axial structures results in a complete loss of epaxial myotomal muscle, whereas hypaxial and limb muscles develop normally. We report that chicken embryos, after surgical removal of the neural tube at the level of the unsegmented paraxial mesoderm, start to develop myotomal cells that express transcripts for the muscle-specific regulators MyoD and myogenin. These cells also make desmin, indicating that the initial steps of axial skeletal muscle formation can occur in the absence of the neural tube. However, a few days following the extirpation, the expression of MyoD and myogenin transcripts gradually disappears, and becomes almost undetectable after 4 days. From these observations we conclude that the neural tube is not required for the generation of the skeletal muscle cell lineage, but may support the survival or maitenance of further differentiation of the myotomal cell compartment. Notochord transplanted medially or laterally to the unsegmented paraxial mesoderm leads to a ventralization of axial structures but does not entirely prevent the early appearance of myoblasts expressing MyoD transcripts. However, the additional notochord inhibits subsequent development and maturation of myotomes. Taken together, our data suggest that neural tube promotes, and notochord inhibits, the process of myogenesis in axial muscles at a developmental step following the initial expression of myogenic bHLH regulators.

scholarly journals Segmental lineage restrictions in the chick embryo spinal cord depend on the adjacent somites

Development ◽  
1991 ◽  
Vol 113 (1) ◽  
pp. 239-244 ◽  
Author(s):  
C.D. Stern ◽  
K.F. Jaques ◽  
T.M. Lim ◽  
S.E. Fraser ◽  
R.J. Keynes
Keyword(s):  
Spinal Cord ◽  
Chick Embryo ◽  
Single Cell ◽  
Neural Tube ◽  
Fluorescent Tracer ◽  
Anteroposterior Axis ◽  
Somite Formation ◽  
Developing Spinal Cord

We have investigated whether the developing spinal cord is intrinsically segmented in its rostrocaudal (anteroposterior) axis by mapping the spread of clones derived from single labelled cells within the neural tube of the chick embryo. A single cell in the ventrolateral neural tube of the trunk was marked in situ with the fluorescent tracer lysinated rhodamine dextran (LRD) and its descendants located after two days of further incubation. We find that clones derived from cells labelled before overt segmentation of the adjacent mesoderm do not respect any boundaries within the neural tube. Those derived from cells marked after mesodermal segmentation, however, never cross an invisible boundary aligned with the middle of each somite, and tend to be elongated along the mediolateral axis of the neural tube. When the somite pattern is surgically disturbed, neighbouring clones derived from neuroectodermal cells labelled after somite formation behave like clones derived from younger cells: they no longer respect any boundaries, and are not elongated mediolaterally. These results indicate that periodic lineage restrictions do exist in the developing spinal cord of the chick embryo, but their maintenance requires the presence of the adjacent somite mesoderm.

Notochord signals control the transcriptional cascade of myogenic bHLH genes in somites of quail embryos

Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1475-1488 ◽  
Author(s):  
M.E. Pownall ◽  
K.E. Strunk ◽  
C.P. Emerson
Keyword(s):  
Gene Expression ◽  
Neural Tube ◽  
Bhlh Gene ◽  
Lateral Plate ◽  
Ventral Neural Tube ◽  
Bhlh Genes ◽  
Somite Formation ◽  
Necessary And Sufficient ◽  
Alpha Actin

Microsurgical, tissue grafting and in situ hybridization techniques have been used to investigate the role of the neural tube and notochord in the control of the myogenic bHLH genes, QmyoD, Qmyf5, Qmyogenin and the cardiac alpha-actin gene, during somite formation in stage 12 quail embryos. Our results reveal that signals from the axial neural tube/notochord complex control both the activation and the maintenance of expression of QmyoD and Qmyf5 in myotomal progenitor cells during the period immediately following somite formation and prior to myotome differentiation. QmyoD and Qmyf5 expression becomes independent of axial signals during myotome differentiation when somites activate expression of Qmyogenin and alpha-actin. Ablation studies reveal that the notochord controls QmyoD activation and the initiation of the transcriptional cascade of myogenic bHLH genes as epithelial somites condense from segmental plate mesoderm. The dorsal medial neural tube then contributes to the maintenance of myogenic bHLH gene expression in newly formed somites. Notochord grafts can activate ectopic QmyoD expression during somite formation, establishing that the notochord is a necessary and sufficient source of diffusible signals to initiate QmyoD expression. Myogenic bHLH gene expression is localized to dorsal medial cells of the somite by inhibitory signals produced by the lateral plate and ventral neural tube. Signaling models for the activation and maintenance of myogenic gene expression and the determination of myotomal muscle in somites are discussed.

Regulation of genes for the cdc25 phosphatases is important for checkpoint control during the cell division cycle

2001 ◽  
Vol 120 (5) ◽  
pp. A501-A501
Author(s):  
U HAUGWITZ ◽  
M WIEDMANN ◽  
K SPIESBACH ◽  
K ENGELAND ◽  
J MOSSNER
Keyword(s):  
Cell Division ◽  
Cell Division Cycle ◽  
Checkpoint Control

ABOUT SOME PECULIARITIES OF THE PHYSIOLOGICAL HETEROGENEITY OF THE POPULATION OF SCENEDESMUS QUADRICAUDA (TURP.) BREB. IN THE PRESENCE OF LOW CONCENTRATIONS OF METALS

2018 ◽  
pp. 34-43
Author(s):  
V. I. Ipatova ◽  
A. G. Dmitrieva ◽  
О. F. Filenko ◽  
T. V. Drozdenko
Keyword(s):  
Cell Division ◽  
Toxic Effect ◽  
Copper Chloride ◽  
Single Cells ◽  
Physiological State ◽  
Scenedesmus Quadricauda ◽  
Physiological Status ◽  
Lag Phase ◽  
Protective Mechanism ◽  
Low Concentrations

The structure of the laboratory population of green microalgae Scenedesmus quadricauda (Turp.) Breb (=Desmodesmus communis E. Hegew.) was studied at different stages of its growth (lag-phase, log-phase and stationary phase) at low concentrations of copper chloride and silver nitrate by the method microculture, allowing to monitor the state and development of single cells having different physiological status. The response of the culture of S. quadricauda - the change in the number of cells and the fractional composition (the fraction of dividing, «dormant» and dying cells) depended not only on the concentration of the toxicant in the medium, but also on the physiological state of the culture: the level of synchronization and the growth phase. Silver ions at low concentrations had a more pronounced toxic effect on the culture than copper ions at different phases of its development, especially at a concentration of 0.001 mg/l (10-9 M). The main mechanism of the toxic effect of metals is to inhibit the process of cell division. At low concentrations of toxicants, especially at a concentration of 0.001 mg/l, a «paradoxical» effect expressed in the predominance of the fraction of «dormant» cells was revealed. The temporary inhibition of the process of cell division can be regarded as a protective mechanism that allows preserving the integrity of the population and its ability to survive in a changing environment. The obtained data explain the effect of action of low concentrations of substances due to their inclusion in the cell, the subsequent accumulation in the cell and their low excretion.

scholarly journals A Molecular Modeling Approach to Identify Potential Antileishmanial Compounds Against the Cell Division Cycle (cdc)-2-Related Kinase 12 (CRK12) Receptor of Leishmania donovani

Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 458
Author(s):  
Emmanuel Broni ◽  
Samuel K. Kwofie ◽  
Seth O. Asiedu ◽  
Whelton A. Miller ◽  
Michael D. Wilson
Keyword(s):  
Natural Products ◽  
Cell Division ◽  
Leishmania Donovani ◽  
Therapeutic Potential ◽  
Neglected Tropical Diseases ◽  
Binding Pocket ◽  
Cell Division Cycle ◽  
World Health ◽  
Atp Binding ◽  
African Flora

The huge burden of leishmaniasis caused by the trypanosomatid protozoan parasite Leishmania is well known. This illness was included in the list of neglected tropical diseases targeted for elimination by the World Health Organization. However, the increasing evidence of resistance to existing antimonial drugs has made the eradication of the disease difficult to achieve, thus warranting the search for new drug targets. We report here studies that used computational methods to identify inhibitors of receptors from natural products. The cell division cycle-2-related kinase 12 (CRK12) receptor is a plausible drug target against Leishmania donovani. This study modelled the 3D molecular structure of the L. donovani CRK12 (LdCRK12) and screened for small molecules with potential inhibitory activity from African flora. An integrated library of 7722 African natural product-derived compounds and known inhibitors were screened against the LdCRK12 using AutoDock Vina after performing energy minimization with GROMACS 2018. Four natural products, namely sesamin (NANPDB1649), methyl ellagic acid (NANPDB1406), stylopine (NANPDB2581), and sennecicannabine (NANPDB6446) were found to be potential LdCRK12 inhibitory molecules. The molecular docking studies revealed two compounds NANPDB1406 and NANPDB2581 with binding affinities of −9.5 and −9.2 kcal/mol, respectively, against LdCRK12 which were higher than those of the known inhibitors and drugs, including GSK3186899, amphotericin B, miltefosine, and paromomycin. All the four compounds were predicted to have inhibitory constant (Ki) values ranging from 0.108 to 0.587 μM. NANPDB2581, NANPDB1649 and NANPDB1406 were also predicted as antileishmanial with Pa and Pi values of 0.415 and 0.043, 0.391 and 0.052, and 0.351 and 0.071, respectively. Molecular dynamics simulations coupled with molecular mechanics Poisson–Boltzmann surface area (MM/PBSA) computations reinforced their good binding mechanisms. Most compounds were observed to bind in the ATP binding pocket of the kinase domain. Lys488 was predicted as a key residue critical for ligand binding in the ATP binding pocket of the LdCRK12. The molecules were pharmacologically profiled as druglike with inconsequential toxicity. The identified molecules have scaffolds that could form the backbone for fragment-based drug design of novel leishmanicides but warrant further studies to evaluate their therapeutic potential.

scholarly journals Cell fate clusters in ICM organoids arise from cell fate heredity and division: a modelling approach

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tim Liebisch ◽  
Armin Drusko ◽  
Biena Mathew ◽  
Ernst H. K. Stelzer ◽  
Sabine C. Fischer ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Division ◽  
Cell Fate ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Lineage ◽  
Cell Fate Decision ◽  
Cell Fate Decisions ◽  
Chemical Signalling ◽  
Fate Decision

AbstractDuring the mammalian preimplantation phase, cells undergo two subsequent cell fate decisions. During the first decision, the trophectoderm and the inner cell mass are formed. Subsequently, the inner cell mass segregates into the epiblast and the primitive endoderm. Inner cell mass organoids represent an experimental model system, mimicking the second cell fate decision. It has been shown that cells of the same fate tend to cluster stronger than expected for random cell fate decisions. Three major processes are hypothesised to contribute to the cell fate arrangements: (1) chemical signalling; (2) cell sorting; and (3) cell proliferation. In order to quantify the influence of cell proliferation on the observed cell lineage type clustering, we developed an agent-based model accounting for mechanical cell–cell interaction, i.e. adhesion and repulsion, cell division, stochastic cell fate decision and cell fate heredity. The model supports the hypothesis that initial cell fate acquisition is a stochastically driven process, taking place in the early development of inner cell mass organoids. Further, we show that the observed neighbourhood structures can emerge solely due to cell fate heredity during cell division.

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