Faculty Opinions recommendation of Mechanics of Fluid-Filled Interstitial Gaps. II. Gap Characteristics in Xenopus Embryonic Ectoderm.

We report here on the consequences of reducing the expression of EP-cadherin at the earliest stages of Xenopus development. Injection of oligodeoxynucleotides antisense to maternal EP-cadherin mRNA into full-grown oocytes reduced the mRNA level in oocytes, and the protein level in blastulae. Adhesion between blastomeres was significantly reduced, as seen in whole embryos, and in assays of the ability of blastomeres to reaggregate in culture. This effect was especially conspicuous in the inner cells of the blastula and included the disruption of the blastocoel. The severity of the EP-cadherin mRNA depletion and of the disaggregation phenotype was dose dependent. This phenotype was rescued by the injection into EP-cadherin mRNA-depleted oocytes of the mRNA coding for a related cadherin, E-cadherin, that is normally expressed at the gastrula stage in the embryonic ectoderm.

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Localization of trophoblast-defined surface antigens during early mouse embryogenesis

Development ◽

10.1242/dev.43.1.147 ◽

1978 ◽

Vol 43 (1) ◽

pp. 147-156

Author(s):

R. F. Searle ◽

E. J. Jenkinson

Keyword(s):

Rabbit Antiserum ◽

Cell Populations ◽

Electron Microscope Level ◽

Cell Stage ◽

Component Cell ◽

Low Levels ◽

Early Mouse ◽

Post Implantation ◽

Embryonic Ectoderm ◽

Ectoplacental Cone

The binding pattern of a rabbit antiserum raised against mouse ectoplacental-cone trophoblast on component cell populations in the pre-implantation and early post-implantation mouse embryo has been examined at the electron-microscope level using an immunoperoxidase-labelling technique. Binding was not detectable on the 1-cell stage, appeared at low levels at the 8-cell stage ana was heavy on the trophectoderm and its trophoblast giant cell and extra-embryonic ectoderm descendants in the post-implantation embryo. In contrast, immunosurgically isolated 3½-day inner cell masses (ICM) showed only slight labelling, whilst ICM derivatives in the 7½-day embryo were unlabelled. The results indicate that the antiserum may be identifying a trophoblast-specific surface determinant(s), which appears with the differentiation of the trophectoderm and is maintained on some of the cell populations derived from this tissue at least until the early postimplantation stages.

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Detrimental effects of two active X chromosomes on early mouse development

Development ◽

10.1242/dev.109.1.189 ◽

1990 ◽

Vol 109 (1) ◽

pp. 189-201 ◽

Cited By ~ 5

Author(s):

N. Takagi ◽

K. Abe

Keyword(s):

X Chromosome ◽

Distal Segment ◽

Translocation Chromosome ◽

Mouse Development ◽

X Chromosomes ◽

Developmental Abnormalities ◽

Inactivation Center ◽

Normal Males ◽

Early Mouse ◽

Embryonic Ectoderm

Matings between female mice carrying Searle's translocation, T(X;16)16H, and normal males give rise to chromosomally unbalanced zygotes with two complete sets of autosomes, one normal X chromosome and one X16 translocation chromosome (XnX16 embryos). Since X chromosome inactivation does not occur in these embryos, probably due to the lack of the inactivation center on X16, XnX16 embryos are functionally disomic for the proximal 63% of the X chromosome and trisomic for the distal segment of chromosome 16. Developmental abnormalities found in XnX16 embryos include: (1) growth retardation detected as early as stage 9, (2) continual loss of embryonic ectoderm cells either by death or by expulsion into the proamniotic cavity, (3) underdevelopment of the ectoplacental cone throughout the course of development, (4) very limited, if any, mesoderm formation, (5) failure in early organogenesis including the embryo, amnion, chorion and yolk sac. Death occurred at 10 days p.c. Since the combination of XO and trisomy 16 does not severely affect early mouse development, it is likely that regulatory mechanisms essential for early embryogenesis do not function correctly in XnX16 embryos due to activity of the extra X chromosome segment of X16.

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