The cytoskeleton and associated proteins during cleavage, compaction and blastocyst differentiation in the pig

Reima, Ilkka; Lehtonen, Eero; Virtanen, Ismo; Fléchon, J.‐E.

doi:10.1111/j.1432-0436.1993.tb00657.x

Cited by 50 publications

(41 citation statements)

References 59 publications

(4 reference statements)

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“…The cell shape changes reported here for the exterior layer of the epiblast during teleost epiboly appeared very similar to those thought to occur during the expansion of the trophectoderm epithelium (Barcroft et al, 1998;Fleming et al, 2001;Reima et al, 1993). Based on morphogenetic arguments, the formation of the mammalian trophectoderm and the epiboly of the teleost blastoderm over the yolk have been suggested to be similar events (Kane and Adams, 2002).…”

Section: A Model For Expansion Of the Epiblast In The Zebrafish Embryosupporting

confidence: 64%

Mutations inhalf baked/E-cadherin block cell behaviors that are necessary for teleost epiboly

2005

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Epiboly, the spreading of the blastoderm over the large yolk cell, is the first morphogenetic movement of the teleost embryo. Examining this movement as a paradigm of vertebrate morphogenesis, we have focused on the epiboly arrest mutant half baked (hab), which segregates as a recessive lethal, including alleles expressing zygotic-maternal dominant (ZMD) effects. Here we show that hab is a mutation in the zebrafish homolog of the adhesion protein E-cadherin. Whereas exclusively recessive alleles of hab produce truncated proteins, dominant alleles all contain transversions in highly conserved amino acids of the extracellular domains, suggesting these alleles produce dominant-negative effects. Antisense oligonucleotides that create specific splicing defects in the hab mRNA phenocopy the recessive phenotypes and, surprisingly, some of the ZMD phenotypes as well. In situ analyses show that during late epiboly hab is expressed in a radial gradient in the non axial epiblast, from high concentrations in the exterior layer of the epiblast to low concentrations in the interior layer of the epiblast. During epiboly, using an asymmetric variant of radial intercalation, epiblast cells from the interior layer sequentially move into the exterior layer and become restricted to that layer; there they participate in subtle cell shape changes that further expand the blastoderm. In hab mutants, when cells intercalate into the exterior layer, they tend to neither change cell shape nor become restricted, and many of these cells 'de-intercalate' and move back into the interior layer. Cell transplantation showed all these defects to be cell-autonomous. Hence, as for the expansion of the mammalian trophoblast at a similar developmental stage, hab/E-cadherin is necessary for the cell rearrangements that spread the teleost blastoderm over the yolk.

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Section: A Model For Expansion Of the Epiblast In The Zebrafish Embryosupporting

confidence: 64%

Mutations inhalf baked/E-cadherin block cell behaviors that are necessary for teleost epiboly

2005

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“…It has been shown previously that epiblast cells within small spherical blastocysts (0-6 mm) have an undifferentiated phenotype [23,24]. They do not express cytokeratins, which are detected only in the mural trophectoderm [25]. In contrast, in larger blastocysts, epiblast cells have already started to differentiate.…”

Section: Discussionmentioning

confidence: 93%

Proliferation and Differentiation of Porcine Inner Cell Mass and Epiblast in Vitro1

Wianny

Perreau

Reviers

1997

Biology of Reproduction

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The proliferation rate and differentiation state were investigated in porcine inner cell masses (ICMs) and epiblasts in vitro. ICMs isolated from early blastocysts (Day 7 of pregnancy) and epiblasts isolated from preelongated blastocysts (Day 11 of pregnancy) were cultured for up to 5 days in the presence of human leukemia inhibitory factor (hLIF) (1000 U/ml). The proliferation rate was evaluated by determination of the percentage of cells in S-phase. The differentiation state was determined by studying the expression of the stage-specific embryonic antigen-1 (SSEA-1), a marker for undifferentiated murine embryonic stem (ES) cells, and the expression of laminin and cytokeratins 8/18, markers of ES cell differentiation. The staining pattern showed that freshly collected Day 11 epiblasts appeared undifferentiated but rapidly lost this characteristic in vitro. A decrease in the proliferation rate was also observed during culture. This decrease was reduced in the presence of high concentrations of hLIF (optimal concentrations: 5000 U/ml). Conversely, treatment of Day 11 epiblast cells with retinoic acid, an agent known to induce differentiation in murine ES cells, caused a dramatic decrease in the proliferation rate in vitro. In contrast to Day 11 epiblasts, Day 7 ICMs expressed SSEA-1 in vitro and showed a higher proliferation rate (p < 0.01). However, their proliferation rate also decreased during culture and following trypsinization. These results indicate that the undifferentiated characteristics of Day 7 ICMs are more likely to be maintained in vitro than are those of Day 11 epiblasts, which are rapidly committed into early differentiation.

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“…This event occurs after the third division in the mouse (Ziomek & Johnson, 1980), but the timing varies among other mammalian species. In the bovine embryo, compaction occurs around the 16-to 32-cell stage, while in the pig the process is completed at the 32-to 64-cell stage (McLaren, 1982;Betteridge and Flechon, 1988;Reima et al, 1993). Compaction is concomitant with the beginning of cell polarisation and represents the onset of the process of cellular differentiation in the mammalian preimplantation embryo (Pratt et ah, 1982).…”

Section: Introductionmentioning

confidence: 97%

Developmentally regulated markers ofin vitro-produced preimplantation bovine embroys

Shehu¹,

Marsicano²,

Fléchon³

et al. 1996

Zygote

Self Cite

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Expression of various developmentally regulated markers was screened throughout the preimplantation stages of in vitro-derived bovine embryos. This was done by investigating the distribution of several nuclear, cytoplasmic and extracellular proteins by means of immunofluorescence microscopy. While lamin B appeared as a constitutive component of nuclei of all preimplantation stages, lamins A/C had a stage-related distribution. The early cleavage stage nuclei contained lamins A/C which generally disappeared in the following stages, with the possible exception of a few positive nuclei in the morula and early blastocyst stage. In the expanded blastocyst stage the nuclei of trophectoderm cells became positive while no positivity was observed in the inner cell mass cells. Starting from day 6, the appearance and/or polarised distribution of various cytoskeletal and cytoskeleton-related components such as Factin, a-catenin and E-cadherin gave an insight into the timing of events related to compaction of bovine embryos. Compaction was correlated with the first differentiation event, i.e. the formation of trophectoderm; this is the first embryonic epithelium, characterised by cytokeratins and desmoplakin. Extracellular fibronectin was first detected in the early blastocyst stage shortly before the morphological differentiation of primitive endoderm, and in the later stages it was localised at the interface between trophectoderm and extraembryonic endoderm. Laminin and collagen IV were expressed by the endoderm cells and contributed to the extracellular matrix underlying the trophectoderm. This study is a first attempt to characterise the cells of in vitro-derived bovine embryos valid for cell line derivation.

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The cytoskeleton and associated proteins during cleavage, compaction and blastocyst differentiation in the pig

Cited by 50 publications

References 59 publications

Mutations inhalf baked/E-cadherin block cell behaviors that are necessary for teleost epiboly

Mutations inhalf baked/E-cadherin block cell behaviors that are necessary for teleost epiboly

Proliferation and Differentiation of Porcine Inner Cell Mass and Epiblast in Vitro1

Developmentally regulated markers ofin vitro-produced preimplantation bovine embroys

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