Culture of Embryonic Cells for Analysis of Amphibian and Mammalian Early Embryogenesis

Cell lineage determination during early embryogenesis has profound effects on adult animal development. Pre-patterning of embryos, such as that of Drosophila and Caenorhabditis elegans, is driven by asymmetrically localized maternal or zygotic factors, including mRNA species and RNA binding proteins. However, it is not clear how mammalian early embryogenesis is regulated and what the early cell fate determinants are. Here we show that, in mouse, mitochondrial ribosomal RNAs (mtrRNAs) are differentially distributed between 2-cell sister blastomeres. This distribution pattern is not related to the overall quantity or activity of mitochondria which appears equal between 2-cell sister blastomeres. Like in lower species, 16S mtrRNA is found to localize in the cytoplasm outside of mitochondria in mouse 2-cell embryos. Alterations of 16S mtrRNA levels in one of the 2-cell sister blastomere via microinjection of either sense or anti-sense RNAs drive its progeny into different cell lineages in blastocyst. These results indicate that mtrRNAs are differentially distributed among embryonic cells at the beginning of embryogenesis in mouse and they are functionally involved in the regulation of cell lineage allocations in blastocyst, suggesting an underlying molecular mechanism that regulates pre-implantation embryogenesis in mouse.

Download Full-text

Lineage commitment of embryonic cells involves MEK1-dependent clearance of pluripotency regulator Ventx2

eLife ◽

10.7554/elife.21526 ◽

2017 ◽

Vol 6 ◽

Cited By ~ 2

Author(s):

Pierluigi Scerbo ◽

Leslie Marchal ◽

Laurent Kodjabachian

Keyword(s):

Cell Division ◽

Cell Fate ◽

Early Embryogenesis ◽

Embryonic Cells ◽

Pluripotent Cells ◽

Embryonic Tissues ◽

Pluripotency Gene ◽

Related Transcription Factor ◽

Over Time

During early embryogenesis, cells must exit pluripotency and commit to multiple lineages in all germ-layers. How this transition is operated in vivo is poorly understood. Here, we report that MEK1 and the Nanog-related transcription factor Ventx2 coordinate this transition. MEK1 was required to make Xenopus pluripotent cells competent to respond to all cell fate inducers tested. Importantly, MEK1 activity was necessary to clear the pluripotency protein Ventx2 at the onset of gastrulation. Thus, concomitant MEK1 and Ventx2 knockdown restored the competence of embryonic cells to differentiate. Strikingly, MEK1 appeared to control the asymmetric inheritance of Ventx2 protein following cell division. Consistently, when Ventx2 lacked a functional PEST-destruction motif, it was stabilized, displayed symmetric distribution during cell division and could efficiently maintain pluripotency gene expression over time. We suggest that asymmetric clearance of pluripotency regulators may represent an important mechanism to ensure the progressive assembly of primitive embryonic tissues.

Download Full-text

Stellaria media embryogenesis: the development and ultrastructure of the suspensor

Canadian Journal of Botany ◽

10.1139/b74-076 ◽

1974 ◽

Vol 52 (3) ◽

pp. 607-614 ◽

Cited By ~ 35

Author(s):

William Newcomb ◽

L. C. Fowke

Keyword(s):

Subsequent Development ◽

Early Embryogenesis ◽

The Other ◽

Structural Level ◽

Embryonic Cells ◽

Cell Type ◽

Stellaria Media ◽

Side Walls ◽

Metabolic Activities ◽

Suspensor Cells

As early as the three-celled stage of embryogenesis, the basal cell of chickweed, Stellaria media, is larger than the other embryonic cells and contains large differentiating plastids, microbodies, and wall ingrowths of the transfer cell type at the micropylar end of the cell. Subsequent development produces a suspensor with unique plastids, microbodies, and extensive profiles of dilated endoplasmic reticulum not found in the embryo proper. The suspensor plastids, which appear to be different from any other plastids previously described on the ultra-structural level, are large and contain two types of tubules and electron-translucent inclusions. Plasmodesmata occur in the end walls but not in the side walls of the suspensor cells. It is suggested that the suspensor of chickweed is involved in important, possibly essential, translocation and metabolic activities during early embryogenesis.

Download Full-text

Visualization of early embryos of the butterfly Bicyclus anynana

Zygote ◽

10.1017/s0967199405003163 ◽

2005 ◽

Vol 13 (2) ◽

pp. 139-144 ◽

Cited By ~ 4

Author(s):

Jarod Masci ◽

Antónia Monteiro

Keyword(s):

Fluorescence Microscopy ◽

Preliminary Data ◽

Uv Light ◽

Developmental Rate ◽

Early Embryo ◽

Early Embryogenesis ◽

Egg Laying ◽

Embryonic Cells ◽

Bicyclus Anynana ◽

Early Embryos

We report on the first attempts, using both light and fluorescence microscopy, to visualize the developing embryo of the butterfly Bicyclus anynana. We developed a new protocol that enabled the clear visualization of the internal egg structures in early embryogenesis (1–24 h after egg laying). Dechorionation was followed by fixation and physical dissection of the external egg structures. Observations of embryonic and extra-embryonic cells were made using a Hoechst nuclear stain that fluoresces in the blue spectrum when bound to DNA and excited with ultraviolet (UV) light under a fluorescence microscope. Preliminary data on the developmental rate of the early embryo are also presented.

Download Full-text

Regulation of the Xenopus laevis transcription factor IIIA gene during oogenesis and early embryogenesis: Negative elements repress the O-TFIIIA promoter in embryonic cells

Developmental Biology ◽

10.1016/0012-1606(91)90123-k ◽

1991 ◽

Vol 145 (2) ◽

pp. 241-254 ◽

Cited By ~ 13

Author(s):

Samuel L. Pfaff ◽

Robert K. Hall ◽

Guy C. Hart ◽

William L. Taylor

Keyword(s):

Transcription Factor ◽

Xenopus Laevis ◽

Early Embryogenesis ◽

Embryonic Cells ◽

Transcription Factor Iiia

Download Full-text

Laser Scanning Confocal Microscopy and Three-Dimesnsional Reconstruction of the Mitotic Spindles of Unequally Dividing Embryonic Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158376 ◽

1990 ◽

Vol 48 (3) ◽

pp. 166-167

Author(s):

J. Holy ◽

G. Schatten

Keyword(s):

Confocal Microscopy ◽

Mitotic Spindle ◽

Laser Scanning ◽

Three Dimensional ◽

Laser Scanning Confocal Microscopy ◽

Two Dimensions ◽

Embryonic Cells ◽

Mitotic Spindles ◽

Cleavage Division ◽

Scanning Confocal Microscopy

One of the classic limitations of light microscopy has been the fact that three dimensional biological events could only be visualized in two dimensions. Recently, this shortcoming has been overcome by combining the technologies of laser scanning confocal microscopy (LSCM) and computer processing of microscopical data by volume rendering methods. We have employed these techniques to examine morphogenetic events characterizing early development of sea urchin embryos. Specifically, the fourth cleavage division was examined because it is at this point that the first morphological signs of cell differentiation appear, manifested in the production of macromeres and micromeres by unequally dividing vegetal blastomeres.The mitotic spindle within vegetal blastomeres undergoing unequal cleavage are highly polarized and develop specialized, flattened asters toward the micromere pole. In order to reconstruct the three-dimensional features of these spindles, both isolated spindles and intact, extracted embryos were fluorescently labeled with antibodies directed against either centrosomes or tubulin.

Download Full-text