Abstract
The entry of β-catenin into vegetal cell nuclei beginning at the 16-cell stage is one of the earliest known molecular asymmetries seen along the animal-vegetal axis in the sea urchin embryo. Nuclear β-catenin activates a vegetal signaling cascade that mediates micromere specification and specification of the endomesoderm in the remaining cells of the vegetal half of the embryo. Only a few potential target genes of nuclear β-catenin have been functionally analyzed in the sea urchin embryo. Here, we show that SpWnt8, a Wnt8 homolog from Strongylocentrotus purpuratus, is zygotically activated specifically in 16-cell-stage micromeres in a nuclear β-catenin-dependent manner, and its expression remains restricted to the micromeres until the 60-cell stage. At the late 60-cell stage nuclear β-catenin-dependent SpWnt8 expression expands to the veg2 cell tier. SpWnt8 is the only signaling molecule thus far identified with expression localized to the 16-60-cell stage micromeres and the veg2 tier. Overexpression of SpWnt8 by mRNA microinjection produced embryos with multiple invagination sites and showed that, consistent with its localization, SpWnt8 is a strong inducer of endoderm. Blocking SpWnt8 function using SpWnt8 morpholino antisense oligonucleotides produced embryos that formed micromeres that could transmit the early endomesoderm-inducing signal, but these cells failed to differentiate as primary mesenchyme cells. SpWnt8-morpholino embryos also did not form endoderm, or secondary mesenchyme-derived pigment and muscle cells, indicating a role for SpWnt8 in gastrulation and in the differentiation of endomesodermal lineages. These establish SpWnt8 as a critical component of the endomesoderm regulatory network in the sea urchin embryo.
| Original language | English |
|---|---|
| Pages (from-to) | 194-205 |
| Number of pages | 12 |
| Journal | Genesis |
| Volume | 39 |
| Issue number | 3 |
| DOIs | |
| State | Published - Jul 1 2004 |
| Externally published | Yes |
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Keywords
- Differentiation
- Embryo
- Endomesoderm
- Gastrulation
- Primary mesenchyme cells
- Sea urchin
- Wnt8
ASJC Scopus subject areas
- Genetics
Cite this
Nuclear β-catenin-dependent Wnt8 signaling in vegetal cells of the early sea urchin embryo regulates gastrulation and differentiation of endoderm and mesodermal cell lineages. / Wikramanayake, Athula; Peterson, Robert; Chen, Jing; Huang, Ling; Bince, Joanna M.; McClay, David R.; Klein, William H.
In: Genesis, Vol. 39, No. 3, 01.07.2004, p. 194-205.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Nuclear β-catenin-dependent Wnt8 signaling in vegetal cells of the early sea urchin embryo regulates gastrulation and differentiation of endoderm and mesodermal cell lineages
AU - Wikramanayake, Athula
AU - Peterson, Robert
AU - Chen, Jing
AU - Huang, Ling
AU - Bince, Joanna M.
AU - McClay, David R.
AU - Klein, William H.
PY - 2004/7/1
Y1 - 2004/7/1
N2 - The entry of β-catenin into vegetal cell nuclei beginning at the 16-cell stage is one of the earliest known molecular asymmetries seen along the animal-vegetal axis in the sea urchin embryo. Nuclear β-catenin activates a vegetal signaling cascade that mediates micromere specification and specification of the endomesoderm in the remaining cells of the vegetal half of the embryo. Only a few potential target genes of nuclear β-catenin have been functionally analyzed in the sea urchin embryo. Here, we show that SpWnt8, a Wnt8 homolog from Strongylocentrotus purpuratus, is zygotically activated specifically in 16-cell-stage micromeres in a nuclear β-catenin-dependent manner, and its expression remains restricted to the micromeres until the 60-cell stage. At the late 60-cell stage nuclear β-catenin-dependent SpWnt8 expression expands to the veg2 cell tier. SpWnt8 is the only signaling molecule thus far identified with expression localized to the 16-60-cell stage micromeres and the veg2 tier. Overexpression of SpWnt8 by mRNA microinjection produced embryos with multiple invagination sites and showed that, consistent with its localization, SpWnt8 is a strong inducer of endoderm. Blocking SpWnt8 function using SpWnt8 morpholino antisense oligonucleotides produced embryos that formed micromeres that could transmit the early endomesoderm-inducing signal, but these cells failed to differentiate as primary mesenchyme cells. SpWnt8-morpholino embryos also did not form endoderm, or secondary mesenchyme-derived pigment and muscle cells, indicating a role for SpWnt8 in gastrulation and in the differentiation of endomesodermal lineages. These establish SpWnt8 as a critical component of the endomesoderm regulatory network in the sea urchin embryo.
AB - The entry of β-catenin into vegetal cell nuclei beginning at the 16-cell stage is one of the earliest known molecular asymmetries seen along the animal-vegetal axis in the sea urchin embryo. Nuclear β-catenin activates a vegetal signaling cascade that mediates micromere specification and specification of the endomesoderm in the remaining cells of the vegetal half of the embryo. Only a few potential target genes of nuclear β-catenin have been functionally analyzed in the sea urchin embryo. Here, we show that SpWnt8, a Wnt8 homolog from Strongylocentrotus purpuratus, is zygotically activated specifically in 16-cell-stage micromeres in a nuclear β-catenin-dependent manner, and its expression remains restricted to the micromeres until the 60-cell stage. At the late 60-cell stage nuclear β-catenin-dependent SpWnt8 expression expands to the veg2 cell tier. SpWnt8 is the only signaling molecule thus far identified with expression localized to the 16-60-cell stage micromeres and the veg2 tier. Overexpression of SpWnt8 by mRNA microinjection produced embryos with multiple invagination sites and showed that, consistent with its localization, SpWnt8 is a strong inducer of endoderm. Blocking SpWnt8 function using SpWnt8 morpholino antisense oligonucleotides produced embryos that formed micromeres that could transmit the early endomesoderm-inducing signal, but these cells failed to differentiate as primary mesenchyme cells. SpWnt8-morpholino embryos also did not form endoderm, or secondary mesenchyme-derived pigment and muscle cells, indicating a role for SpWnt8 in gastrulation and in the differentiation of endomesodermal lineages. These establish SpWnt8 as a critical component of the endomesoderm regulatory network in the sea urchin embryo.
KW - Differentiation
KW - Embryo
KW - Endomesoderm
KW - Gastrulation
KW - Primary mesenchyme cells
KW - Sea urchin
KW - Wnt8
UR - http://www.scopus.com/inward/record.url?scp=4043087613&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=4043087613&partnerID=8YFLogxK
U2 - 10.1002/gene.20045
DO - 10.1002/gene.20045
M3 - Article
C2 - 15282746
AN - SCOPUS:4043087613
VL - 39
SP - 194
EP - 205
JO - Genesis
JF - Genesis
SN - 1526-954X
IS - 3
ER -