scholarly journals The Developmental Capacity of Nuclei Taken from Differentiating Endoderm Cells of Xenopus laevis

Development ◽  
1960 ◽  
Vol 8 (4) ◽  
pp. 505-526
Author(s):  
J. B. Gurdon
Keyword(s):  
Xenopus Laevis ◽  
Rana Pipiens ◽  
Nuclear Transplantation ◽  
Blastula Stage ◽  
Developmental Capacity ◽  
Nuclear Changes ◽  
Nuclear Differentiation ◽  
Development Proceeds ◽  
Transplantation Experiments ◽  
Different Parts

An important question concerning embryonic differentiation is whether the nuclei of somatic cells in different parts of an embryo come to differ genetically from each other during development. It has become possible to investigate this matter since King & Briggs (1955) have shown that nuclear transplantation is a satisfactory technique for testing the developmental potentialities of embryonic nuclei. These authors (1957, 1960) have used Rana pipiens for transplantation experiments with endoderm nuclei, and have found that these nuclei become progressively limited in their developmental capacity after the late blastula stage. This paper describes some similar experiments carried out with endoderm nuclei of Xenopus laevis. The general conclusion that nuclei change as development proceeds is confirmed; there are, however, considerable differences between Rana and Xenopus in the rate and time of onset of nuclear changes. These differences make it easier to understand the significance of nuclear differentiation during embryonic development.

A Description of the Technique for Nuclear Transplantation in Xenopus laevis

Development ◽  
1960 ◽  
Vol 8 (4) ◽  
pp. 437-444
Author(s):  
T. R. Elsdale ◽  
J. B. Gurdon ◽  
M. Fischberg
Keyword(s):  
Xenopus Laevis ◽  
Rana Pipiens ◽  
Nuclear Transplantation ◽  
Laboratory Conditions ◽  
Technical Details ◽  
Comparison Of The Results ◽  
Transplantation Experiments

A Method by which nuclei can be successfully transplanted into Amphibian eggs was first worked out by Briggs & King (1952) for the eggs of Rana pipiens. Xenopus laevis is an atypical Anuran since its eggs can be obtained throughout the year, and the resulting embryos can be reared to maturity within 12 months under laboratory conditions. Because of these advantages we have used Xenopus for nuclear transplantation experiments. Though the principle of Briggs & King's technique has been followed, differences between the eggs of Rana and Xenopus have made it necessary to modify their technique before it can be satisfactorily applied to the eggs of Xenopus. The purpose of this publication is first to give technical details of these modifications, and secondly to discuss the extent to which they might affect a direct comparison of the results of transplantations in Rana and Xenopus.

The Developmental Capacity of Nuclei taken from Intestinal Epithelium Cells of Feeding Tadpoles

Development ◽  
1962 ◽  
Vol 10 (4) ◽  
pp. 622-640 ◽  
Author(s):  
J. B. Gurdon
Keyword(s):  
Genetic Information ◽  
Cellular Differentiation ◽  
Cell Types ◽  
Nuclear Transplantation ◽  
Differentiated Cells ◽  
Developmental Capacity ◽  
Nuclear Changes ◽  
Different Cell Types ◽  
Epithelium Cells ◽  
Saline Medium

An important problem in embryology is whether the differentiation of cells depends upon a stable restriction of the genetic information contained in their nuclei. The technique of nuclear transplantation has shown to what extent the nuclei of differentiating cells can promote the formation of different cell types (e.g. King & Briggs, 1956; Gurdon, 1960c). Yet no experiments have so far been published on the transplantation of nuclei from fully differentiated normal cells. This is partly because it is difficult to obtain meaningful results from such experiments. The small amount of cytoplasm in differentiated cells renders their nuclei susceptible to damage through exposure to the saline medium, and this makes it difficult to assess the significance of the abnormalities resulting from their transplantation. It is, however, very desirable to know the developmental capacity of such nuclei, since any nuclear changes which are necessarily involved in cellular differentiation must have already taken place in cells of this kind.

Ploidy, pigment patterns and species specific antigenicity in interspecific nuclear transplantations in newts

Development ◽  
1967 ◽  
Vol 17 (2) ◽  
pp. 319-330
Author(s):  
F. Sládeček ◽  
A. Romanovský
Keyword(s):  
Xenopus Laevis ◽  
Functional Activity ◽  
Nuclear Transplantation ◽  
Skin Grafts ◽  
Species Specific ◽  
Transplantation Antigens ◽  
Transplantation Experiments ◽  
Pigment Patterns

It was shown by Simnett (1964) that in Xenopus laevis skin grafts in adult frogs between members of the same nuclear clone were tolerated in the same way as autografts, but in skin grafts made between individuals belonging to different nuclear clones a homograft rejection occurred. The nucleus is therefore responsible for the synthesis of specific transplantation antigens. It seemed to us useful to investigate the species-specific antigenicity of animals derived from eggs transplanted with foreign nuclei in correlation with their ploidy and with the development of their species-specific pigment patterns, as a proof of functional activity of transplanted nuclei. For this purpose we used two species of Triturus, T. vulgaris and T. alpestris, because of earlier studies carried out in our laboratory on the pigmentation of their hybrids (Romanovský & Ŝtefanová, 960; Mazáková-Štefanová, 1965) and on their species-specific antigenicity (Romanovský, 1962 a, b), in spite of the known difficulties and limitations of nuclear transplantation experiments in these species (Lehman, 1955; Sládeček & Mazáková-Štefanová, 1964, 1965).

The Effects of Ultraviolet Irradiation on Uncleaved Eggs of Xenopus Laevis

1960 ◽  
Vol s3-101 (55) ◽  
pp. 299-311
Author(s):  
J. B. GURDON
Keyword(s):  
Xenopus Laevis ◽  
Ultraviolet Irradiation ◽  
Sperm Nucleus ◽  
Nuclear Transplantation ◽  
Vitelline Membrane ◽  
Nuclear Marker ◽  
Small Doses ◽  
Transplantation Experiments ◽  
Better Than

The effects are described of ultraviolet (u.v.) irradiation upon the eggs of Xenopus laevis. The results obtained apply to fertilized eggs and also to unfertilized eggs into which blastula nuclei have been transplanted. Eggs were irradiated up to 20 min after laying, for periods varying from 15 to 50 sec. The egg nucleus is completely inactivated by small doses of u.v. If fertilized eggs are used this gives rise to haploids, which the use of a nuclear marker has shown to be androgenetic. After irradiation the egg nucleus descends towards the centre of the egg, and comes to lie adjacent to the transplanted or sperm nucleus. At the first mitosis, however, it does not fuse but remains as a pycnotic clump in the centre of the spindle. Soon after this it disappears, without disintegrating into visible fragments. The transplanted or sperm nucleus appears to be unaffected by the irradiation and death of the egg nucleus. The egg cytoplasm does not appear to be damaged, even after doses of u.v. which are considerably more than sufficient to kill the egg nucleus. The main reasons for this belief are that haploids obtained by other means develop no better than those obtained by u.v. An increase of u.v. treatment from 30 to 80 sec results in no increase in abnormalities sustained. The jelly is broken down and the vitelline membrane weakened. This enables the egg to be penetrated by a micropipette without causing damage or preventing healing. This investigation was undertaken to facilitate the analysis of nuclear transplantation experiments in Xenopus. The increased penetrability of eggs is of technical value for this purpose. The interpretation of these experiments is greatly facilitated by the knowledge that the egg cytoplasm need not be damaged by the u.v. and that the egg nucleus is completely inactivated so as not to interfere with the development of the egg.

Development of the Xenopus laevis hatching gland and its relationship to surface ectoderm patterning

Development ◽  
1991 ◽  
Vol 111 (2) ◽  
pp. 469-478 ◽  
Author(s):  
T.A. Drysdale ◽  
R.P. Elinson
Keyword(s):  
Retinoic Acid ◽  
Tyrosine Hydroxylase ◽  
Xenopus Laevis ◽  
Ciliated Cells ◽  
Surface Ectoderm ◽  
Gland Cells ◽  
The Face ◽  
Underlying Mechanisms ◽  
Development Proceeds ◽  
Hatching Gland

An antibody that recognizes tyrosine hydroxylase can be used as a marker for hatching gland cells in Xenopus embryos. Using this marker, we have shown that hatching gland cells are induced at the end of gastrulation and that presumptive hatching gland cells are localized to the anterior neural folds in Xenopus. The movements of neurulation bring the hatching gland cells together to form a characteristic Y pattern on the dorsoanterior surface of the head. The Y pattern delineates several zones of surface ectoderm which can be visualized by the presence or absence of ciliated cells. As development proceeds the hatching gland pattern is altered, demonstrating the active changes involved in forming the face. Lithium, UV irradiation and retinoic acid can be used to alter the hatching gland pattern in specific ways which help to understand the underlying mechanisms of ectodermal patterning.

An Experimental Analysis of the Development of the Haploid Syndrome in Embryos of Xenopus laevis

Development ◽  
1963 ◽  
Vol 11 (1) ◽  
pp. 267-278
Author(s):  
Louie Hamilton
Keyword(s):  
Xenopus Laevis ◽  
Experimental Analysis ◽  
Rana Pipiens ◽  
Animal Pole ◽  
Pole Cells

Haploid vertebrates may occur spontaneously but are very rare (Fankhauser, 1941; Humphrey & Fankhauser, 1957); however, haploids may be experimentally produced in fish (Swarup, 1959) and in mammals (Beatty, 1953), while amphibian eggs may be so treated that all developing embryos are haploid (Porter, 1939; Gurdon, 1960). The full descriptions of the development of haploid Rana pipiens (Porter, 1939) and R. nigromaculata (Miyada, 1960) apply so well to Xenopus laevis that only the most important points will be touched on here. Haploid amphibians may be identified at the beginning of gastrulation since their animal pole cells are smaller at a given stage than are those of diploids. In all haploid Anura the onset of gastrulation is delayed, and thereafter haploids become progressively more retarded in their development. Their neural plates are shorter, and when the neural folds have closed it can be seen that the embryos are microcephalic and suffer from lordosis and a bulging abdomen.

Static Pressure-Volume Curves for the Lung of the Frog (Rana Pipiens)

1978 ◽  
Vol 76 (1) ◽  
pp. 149-165 ◽  
Author(s):  
G. M. HUGHES ◽  
G. A. VERGARA
Keyword(s):  
Volume Change ◽  
Rana Pipiens ◽  
Static Pressure ◽  
Large Diameter ◽  
The Difference ◽  
Isolated Lungs ◽  
Precise Role ◽  
Different Parts

1. Static pressure/volume curves have been determined for isolated frog lungs inflated with either air or saline. In both cases a hysteresis was present: the pressure required to produce unit change of volume being greater during inflation than deflation. 2. The pressure necessary for a given volume change was less for the saline-filled than the air-filled lungs. The difference between these curves is due to the surface tension at the air/lung interface. 3. Pressure/volume curves for air-filled lungs in situ were similar to curves for isolated lungs. However, a greater pressure was required for the same volume change during both inflation and deflation. 4. Compliance was calculated from different parts of air pressure/volume curves and gave values greater than those obtained using similar calculations for higher vertebrates. 5. These observations support other evidence for the presence of a surfactant in the lung lining of frogs in spite of the relatively large diameter of their ‘alveoli.’ The precise role of such a lining is uncertain and it is concluded that similar forces may be involved during the inflation and deflation of lungs of frogs and higher vertebrates in spite of differences in gross morphology.

Factors Responsible for the Abnormal Development of Embryos Obtained by Nuclear Transplantation in Xenopus laevis

Development ◽  
1960 ◽  
Vol 8 (3) ◽  
pp. 327-340
Author(s):  
J. B. Gurdon
Keyword(s):  
Xenopus Laevis ◽  
Embryo Development ◽  
Normal Development ◽  
Nuclear Transplantation ◽  
Abnormal Development ◽  
Donor Nucleus ◽  
Innate Capacity

In Xenopus the embryos derived from nuclear transplantation often develop abnormally. These abnormalities must be due to the limited potentiality for development of either the donor nucleus or the egg cytoplasm; this limited potentiality will in turn be due to technical damage during transplantation or to the innate condition of the nucleus or cytoplasm before the experiment. The extent to which these technical and innate factors are responsible for abnormalities of transplant-embryo development has been analysed by considering the effect of each factor in turn. Nuclei from early donor stages have been used, since these nuclei are believed to be undifferentiated (see p. 338) and therefore to have the innate capacity for entirely normal development. The effects of other factors have been investigated by experiments in which each factor is varied in different ways. Any correlation between variations in one factor and the resulting proportion of abnormal transplant-embryos is then recorded.

Circular mitochondrial DNA from Xenopus laevis and Rana pipiens

Chromosoma ◽  
1967 ◽  
Vol 20 (4) ◽  
pp. 445-449 ◽  
Author(s):  
David R. Wolstenholme ◽  
Igor B. Dawid
Keyword(s):  
Mitochondrial Dna ◽  
Xenopus Laevis ◽  
Rana Pipiens

scholarly journals Postfertilization deadenylation of mRNAs in Xenopus laevis embryos is sufficient to cause their degradation at the blastula stage.

1997 ◽  
Vol 17 (1) ◽  
pp. 209-218 ◽  
Author(s):  
Y Audic ◽  
F Omilli ◽  
H B Osborne
Keyword(s):  
Xenopus Laevis ◽  
Untranslated Region ◽  
Sequence Information ◽  
Blastula Stage ◽  
Cytoplasmic Polyadenylation ◽  
Cis Acting ◽  
Stage Of Development ◽  
Chimeric Rnas ◽  
Xenopus Laevis Embryos

Although the maternal Xenopus laevis Eg mRNAs are deadenylated after fertilization, they are not immediately degraded and they persist in the embryos as poly(A)- transcripts. The degradation of these RNAs is not detected until the blastula stage of development (6 to 7 h postfertilization). To understand the basis for this delay between deadenylation and degradation, it is necessary to identify the cis-acting element(s) required to trigger degradation in blastula stage embryos. To this end, several chimeric RNAs containing different portions of the 3' untranslated region of Eg2 mRNA were injected into two-cell X. laevis embryos. We observed that only the RNAs that contained the cis-acting elements that confer rapid deadenylation were subsequently degraded at the blastula stage. This suggested that deadenylation may be sufficient to trigger degradation. By injecting chimeric RNAs devoid of Eg sequence information, we further showed that only deadenylated RNAs were degraded in X. laevis embryos. Last, introduction of a functional cytoplasmic polyadenylation element into a poly(A)- RNA, thereby causing its polyadenylation after injection into embryos, protected the RNA from degradation. Hence, in X. laevis embryos, the postfertilization deadenylation of maternal Eg mRNAs is sufficient to cause the degradation of an mRNA, which, however, only becomes apparent at the blastula stage. Possible causes for this delay between deadenylation and degradation are discussed in the light of these results.

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