Characterization of intercellular junctions in the caudal portion of the developing neural tube of the chick embryo

1980 ◽  
Vol 158 (1) ◽  
pp. 29-41 ◽  
Author(s):  
Gary C. Schoenwolf ◽  
Robert O. Kelley
Keyword(s):  
Chick Embryo ◽  
Neural Tube ◽  
Intercellular Junctions ◽  
Caudal Portion

scholarly journals ELECTROPHYSIOLOGICAL EVIDENCE FOR LOW-RESISTANCE INTERCELLULAR JUNCTIONS IN THE EARLY CHICK EMBRYO

1968 ◽  
Vol 37 (3) ◽  
pp. 650-659 ◽  
Author(s):  
Judson D. Sheridan
Keyword(s):  
Chick Embryo ◽  
Neural Tube ◽  
Electrical Coupling ◽  
Intercellular Junctions ◽  
Neural Plate ◽  
Early Chick Embryo ◽  
Low Resistance ◽  
Electrophysiological Evidence ◽  
Electron Microscopical ◽  
Different Tissues

Electrophysiological evidence is presented for the exchange of small ions directly between cells interiors, i.e. "electrical coupling," in the early chick embryo. Experiments with intracellular marking show that coupling is widespread, occurring between cells in the same tissue, e.g. ectoderm, notochord, neural plate, mesoderm, and Hensen's node, and between cells in different tissues, e.g. notochord to neural plate, notochord to neural tube, notochord to mesoderm. The coupling demonstrates the presence of specialized low-resistance intercellular junctions as found in other embryos and numerous adult tissues. The results are discussed in relation to recent electron microscopical studies of intercellular junctions in the early chick embryo. The function of the electrical coupling in embryogenesis remains unknown, but some possibilities are considered.

Overexpression of Snail family members highlights their ability to promote chick neural crest formation

Development ◽  
2002 ◽  
Vol 129 (7) ◽  
pp. 1583-1593 ◽  
Author(s):  
Marta G. del Barrio ◽  
M. Angela Nieto
Keyword(s):  
Chick Embryo ◽  
Neural Crest ◽  
Neural Tube ◽  
Family Members ◽  
Ectopic Expression ◽  
Endogenous Gene ◽  
The Family ◽  
Snail Family ◽  
Migratory Cells ◽  
Snail Gene

The Snail gene family of transcription factors plays crucial roles in different morphogenetic processes during the development of vertebrate and invertebrate embryos. In previous studies of function interference for one of the family members, Slug, we showed its involvement and neural crest formation in the chick embryo. Now we have carried out a series of gain-of-function experiments in which we show that Slug overexpression in the neural tube of the chick embryo induces an increase in neural crest production. The analysis of electroporated embryos shows that Slug can induce the expression of rhoB and an increase in the number of HNK-1-positive migratory cells, indicating that it lies upstream of them in the genetic cascade of neural crest development. The increase in neural crest production after Slug overexpression was confined to the cranial region, indicating that the mechanisms of crest induction somehow differ between head and trunk. The expression of the two vertebrate family members, Slug and Snail, is peculiar with respect to the neural crest. Slug is not expressed in the premigratory crest in the mouse, whereas it is expressed in this cell population in the chick and the opposite is true for Snail(Sefton, M., Sánchez, S. and Nieto M. A. (1998) Development125, 3111-3121). This raises the question of whether they can be functionally equivalent. To test this hypothesis both intra- and interspecies, we have performed a series of ectopic expression experiments by electroporating chick and mouse Snail in the chick embryo hindbrain. We observe that both genes elicit the same responses in the neural tube. Our results indicate that they can be functionally equivalent, although the embryos show a higher response to the endogenous gene, chick Slug.

Intercellular junctions in the developing neural retina of the chick embryo

1970 ◽  
Vol 104 (3) ◽  
pp. 405-418 ◽  
Author(s):  
Joel B. Sheffield ◽  
D. A. Fischman
Keyword(s):  
Chick Embryo ◽  
Intercellular Junctions ◽  
Neural Retina

An experimental analysis of somite segmentation in the chick embryo

Development ◽  
1980 ◽  
Vol 55 (1) ◽  
pp. 93-108
Author(s):  
Ruth Bellairs ◽  
Marianne Veini
Keyword(s):  
Carboxylic Acid ◽  
Chick Embryo ◽  
Neural Tube ◽  
Experimental Analysis ◽  
Collagen Fibrils ◽  
Unoperated Control ◽  
Control Side ◽  
Series Of Experiments

In a previous paper it was suggested that collagen fibrils play an important role in the process of somite segmentation. This paper was designed mainly to test that concept. In one series of experiments, embryos were treated with either αα′-dipyridyl or L-azetidine-2-carboxylic acid, which are analogues that interfere with the formation of normal collagen. The reagents led to a reduction in the numbers of somites that formed, as well as to the production of other anomalies such as overall diminution in size and retardation. The older the embryo at the time of treatment, the further posteriorly were the major anomalies located. It is concluded that these results lend some support to the concept. In a second series of experiments an incision was made along one side of the neural tube and notochord to separate it from the segmental plate on one side. The result was that many more somites formed on the unoperated (control) side of the embryo than on the operated side. It is concluded that these results also lend support to the concept; but that they are of interest also in relation to the mechanisms involved in the control of somite numbers. In a third group of experiments, attempts were made to obtain somites in the absence of endoderm. Although this was not possible using surgery, it was achieved by treating the young embryos with u.v. irradiation. It was concluded that the presence of endoderm is not essential for the segmentation of mesoderm.

Cartilage associated protein (CASP) is a novel developmentally regulated chick embryo protein

1997 ◽  
Vol 110 (12) ◽  
pp. 1351-1359
Author(s):  
P. Castagnola ◽  
M. Gennari ◽  
R. Morello ◽  
L. Tonachini ◽  
O. Marin ◽  
...  
Keyword(s):  
Chick Embryo ◽  
Developmentally Regulated ◽  
Reading Frame ◽  
Amino Terminal ◽  
Nuclear Antigens ◽  
Cartilage Extracellular Matrix ◽  
Low Levels ◽  
Specific Rabbit ◽  
Chicken Protein

A subtracted cDNA library was generated to identify cDNAs specific for chondrocyte mRNAs preferentially expressed at the hypertrophic stage with respect to early differentiation stages. The characterization of a cDNA isolated from this library that hybridizes with a 1.8 kb mRNA is described here. This mRNA is expressed at extremely low levels in dedifferentiated chondrocytes cultured in adherent conditions, at very low levels in differentiating chondrocytes and at very high levels in hypertrophic chondrocytes cultured in suspension conditions. In the developing chick embryo this mRNA is detectable in RNAs extracted from several other tissues besides cartilage. The described cDNA contains a complete open reading frame coding for a polypeptide of about 33 kDa. Homology searches with known cDNA and protein sequences have revealed that the chicken protein is related to the amino-terminal half of two mammalian nuclear antigens. By immunohistochemistry with specific rabbit antisera a strong signal was detected in the cartilage extracellular matrix of selected regions of the developing skeleton. Because of this localization of the antigen we named this protein cartilage associated protein (hereafter referred to as CASP).

The differing effects of occipital and trunk somites on neural development in the chick embryo

Development ◽  
1987 ◽  
Vol 100 (3) ◽  
pp. 525-533 ◽  
Author(s):  
T.M. Lim ◽  
E.R. Lunn ◽  
R.J. Keynes ◽  
C.D. Stern
Keyword(s):  
Chick Embryo ◽  
Neural Crest ◽  
Neural Tube ◽  
Neural Development ◽  
Osmium Tetroxide ◽  
Local Property ◽  
Sensory Cells ◽  
Base Of The Skull ◽  
Atlas And Axis ◽  
Zinc Iodide

In all higher vertebrate embryos the sensory ganglia of the trunk develop adjacent to the neural tube, in the cranial halves of the somite-derived sclerotomes. It has been known for many years that ganglia do not develop in the most cranial (occipital) sclerotomes, caudal to the first somite. Here we have investigated whether this is due to craniocaudal variation in the neural tube or crest, or to an unusual property of the sclerotomes at occipital levels. Using the monoclonal antibody HNK-1 as a marker for neural crest cells in the chick embryo, we find that the crest does enter the cranial halves of the occipital sclerotomes. Furthermore, staining with zinc iodide/osmium tetroxide shows that some of these crest-derived cells sprout axons within these sclerotomes. By stage 23, however, no dorsal root ganglia are present within the five occipital sclerotomes, as assessed both by haematoxylin/eosin and zinc iodide/osmium tetroxide staining. Moreover, despite this loss of sensory cells, motor axons grow out in these segments, many of them later fasciculating to form the hypoglossal nerve. The sclerotomes remain visible until stages 27/28, when they dissociate to form the base of the skull and the atlas and axis vertebrae. After grafting occipital neural tube from quail donor embryos in place of trunk neural tube in host chick embryos, quail-derived ganglia do develop in the trunk sclerotomes. This shows that the failure of occipital ganglion development is not the result of some fixed local property of the neural crest or neural tube at occipital levels. We therefore suggest that in the chick embryo the cranial halves of the five occipital sclerotomes lack factors essential for normal sensory ganglion development, and that these factors are correspondingly present in all the more caudal sclerotomes.

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