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F9 teratocarcinoma stem cells treated with retinoic acid differentiate in suspension into embryoid bodies with an outer layer of visceral endoderm surrounding a core of largely undifferentiated cells. The visceral endoderm-containing embryoid bodies, when plated onto an extracellular matrix coating, give rise to parietal endoderm outgrowth. These in vitro cell cultures mimic both geometrically and biochemically the differentiation of visceral and parietal endoderm in the early mouse embryo and, thus, were used as a model system for the study of molecular and cellular mechanisms underlying the differentiation of the extraembryonic endoderm lineages. We have investigated the expression of syndecan-1, an integral membrane proteoglycan that binds to multiple components of the extracellular matrix and basic FGF, during visceral endoderm differentiation and parietal endoderm outgrowth. Syndecan-1 immunostaining is detected on all cell surfaces in the undifferentiated embryoid bodies and in the differentiating embryoid bodies prior to the formation of the visceral endoderm. Following the differentiation of visceral endoderm, syndecan-1 localizes predominantly to the basal surface of this epithelial layer, while syndecan-1 staining in the core of differentiated embryoid bodies is faint. Quantitation of cell associated syndecan-1 indicates that syndecan-1 is down-regulated during embryoid body differentiation. However, northern analysis shows that the amounts of steady-state syndecan-1 mRNA are the same in undifferentiated versus differentiated embryoid bodies, suggesting post-transcriptional regulation of syndecan-1 expression in the differentiating embryoid body. Analysis of syndecan-1 distribution in the outgrowth culture by immunofluorescence demonstrates that syndecan-1 is absent from the cell surface of parietal endoderm. However, a substantial amount of syndecan-1 is detected inside parietal endoderm cells. While all three cell types release syndecan-1 ectodomain into the culture medium, the parietal endoderm outgrowth releases more syndecan-1 ectodomain than the differentiated embryoid body. These data suggest that the post-transcriptional control and post-translational shedding of syndecan-1 from the cell surface are developmentally regulated during the differentiation of visceral to parietal endoderm and the migration of parietal endoderm.
R Jiang, and
M Kato, and
M Bernfield, and
L B Grabel
January 1989,
Biology of the cell,
R Jiang, and
M Kato, and
M Bernfield, and
L B Grabel
January 1985,
Differentiation; research in biological diversity,
R Jiang, and
M Kato, and
M Bernfield, and
L B Grabel
October 2001,
Molecular reproduction and development,
R Jiang, and
M Kato, and
M Bernfield, and
L B Grabel
May 1997,
Experimental cell research,
R Jiang, and
M Kato, and
M Bernfield, and
L B Grabel
September 2002,
Molecular and cellular endocrinology,
R Jiang, and
M Kato, and
M Bernfield, and
L B Grabel
August 2002,
Functional & integrative genomics,
R Jiang, and
M Kato, and
M Bernfield, and
L B Grabel
March 2005,
Experimental cell research,
R Jiang, and
M Kato, and
M Bernfield, and
L B Grabel
January 1985,
Cold Spring Harbor symposia on quantitative biology,
R Jiang, and
M Kato, and
M Bernfield, and
L B Grabel
September 1988,
Developmental biology,
R Jiang, and
M Kato, and
M Bernfield, and
L B Grabel
September 1988,
Developmental biology,
