The early development of the sheep trophoblast and the involvement of cell death

Carnegie, Jacqueline A.; McCully, M. E.; Robertson, H. A.

doi:10.1002/aja.1001740409

Cited by 24 publications

(13 citation statements)

References 31 publications

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“…In the present work, we have shown cell death in its earliest stages in both the epiblast and endoderm, but at low levels and with apparently random distribution throughout the earlyto late-streak period. By contrast, cell death in the ectoplacental cone during the same period was extensive, as would be expected from previous accounts of cell death in invading trophoblast cells (Carnegie et al 1985).…”

Section: Discussionmentioning

confidence: 64%

“…It has been speculated that cell death at this time serves to eliminate cells of the trophectodermal lineage from the inner cell mass (Pierce et al 1989), but it may also be an early manifestation of the process of cavitation of the embryo, which also seems to rely on cell death (Coucouvanis and Martin 1995). At this time in mammalian development the trophoblast is invading the uterine epithelium, and this process is also accompanied by cell death, both of the epithelial cells, which are subsequently phagocytosed by trophoblast cells (El-Shershaby and Hinchliffe 1975;Parr et al 1987;Welsh and Enders 1987), and of the trophoblast cells themselves (Carnegie et al 1985).…”

Section: Introductionmentioning

confidence: 97%

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Patterns of cell death during gastrulation in chick and mouse embryos

Sanders

Torkkeli

French

1997

Anatomy and Embryology

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We have examined the distribution of cells at an early stage of the cell death process in gastrulating chick and mouse embryos, using a DNA nick end-labelling technique to label nuclei that are undergoing DNA fragmentation in situ. In the chick embryo, the incidence of nuclei showing DNA fragmentation was mapped by digitizing the occurrence of these nuclei from sections, and reconstructing the three separate layers of the entire embryo at several stages of gastrulation. In the chick, DNA fragmentation was found in nuclei throughout the embryo, in cells of all three germ layers, but most especially in the epiblast in the rostral germinal crescent and in the lateral marginal zones. This region of greatest cell death formed an arc rostrally and laterally in the epiblast, and was consistent through gastrulation and into the early neurulation stage. While the extensive cell death in the chick embryo may be due to cell redundancy, it is also possible that the pattern of death observed could be related to the compression of the embryo against the barrier of yolk at the periphery of the area pellucida during expansion. In a number of cases in the chick, local regions of elevated cell death were also observed in the primitive streak. This may be associated with the changing cell-cell and cell-matrix interactions experienced by cells traversing the primitive streak. In the gastrulating mouse embryo, by contrast, nuclei undergoing DNA fragmentation showed no consistent regions of elevated incidence, in any of the embryonic layers. DNA fragmentation in these embryos was, however, observed in nuclei of cells in the visceral endoderm and in the epiblast. The lack of any clear pattern of DNA fragmentation in the mouse embryo at this stage of development leaves the roles of the dying cells enigmatic. The death may, however, be lineage-related or be a reflection of a cellular redundancy necessary in a developing system that is undergoing extensive cell rearrangement and cellular adhesive change.

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Section: Discussionmentioning

confidence: 64%

Section: Introductionmentioning

confidence: 97%

Patterns of cell death during gastrulation in chick and mouse embryos

Sanders

Torkkeli

French

1997

Anatomy and Embryology

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“…Numerous endocytic vesicles and lysosomes have previously been described at this stage in ovine trophoblasts [1,32,33]. It has been evidenced that bovine spherical conceptuses display an increased protein synthesis activity compared with that of elongated trophoblasts [34].…”

Section: Discussionmentioning

confidence: 98%

Identification of Differentially Regulated Genes During Elongation and Early Implantation in the Ovine Trophoblast Using Complementary DNA Array Screening1

Cammas¹,

Reinaud²,

Dubois³

et al. 2005

Biology of Reproduction

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Following hatching, pre-elongated conceptuses undergo elongation by intense proliferation, until implantation. We investigated the changes in gene expression associated with these physiological events using human cDNA arrays containing 2370 known genes. Comparison of pre-elongated, elongated, and implanting trophoblasts allowed the determination of 313 expressed genes, 63 of which were differentially regulated. These were classified into four functional families. Pre-elongated trophoblasts were characterized by preferential expression of genes involved in protein trafficking, whereas only latter developmental stages expressed cell signaling genes and receptors. Among the 63 developmentally regulated genes, four exhibited the highest levels of expression (TMSB10, CTNNA1, NMP1, and CX3CL1). Each of these also represents a functional family and display a specific expression pattern. One of them, CX3CL1 (CX3C chemokine, also known as fractalkine), is a chemokine that seems to have potential importance in trophoblast development, and which deserves further clarification of its role in implantation.

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“…Most of the residual bodies observed in this study contain parts of cells or whole cells in the process of degenerating. It is possible that cell degeneration is a normal feature of blastocyst development, particularly during its expansion phase (Carnegie et al, 1985 …”

Section: Discussionmentioning

confidence: 99%