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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2001-6-12
pubmed:abstractText
Xenopus foxD5a, the full-length fork head gene previously described as a PCR fragment (XFLIP), is first detectable at stage II of oogenesis. Low-abundance maternal transcripts are localized to the animal hemisphere of the cleavage embryo, and protein can be translocated to the nucleus prior to the onset of zygotic transcription. Zygotic expression is strongest in the presumptive neural ectoderm at gastrula and neural plate stages, but there is minor paraxial mesodermal expression during primary gastrulation that becomes significant in the tail bud during secondary gastrulation. Expression of foxD5a in animal cap explants induces elongation and expression of mesodermal, neural-inducing, and early neural-specifying genes, indicating a role in dorsal axis formation. Zygotic foxD5a expression is induced strongly by siamois, moderately by cerberus, weakly by Wnt8 and noggin, and not by chordin in animal cap explants. Expression of foxD5a in whole embryos has differential dorsal and ventral effects. Ventral mRNA injection induces partial secondary axes composed of expanded mesodermal and epidermal tissues, but does not induce ectopic neural tissues. Dorsal mRNA injection causes hypertrophy of the neural plate and expansion of early neural genes (sox3 and otx2), but this is not the result of increased proliferation or expanded neural-inducing mesoderm. The neural plate appears to be maintained in an immature state because otx2 expression is expanded and expression of en2, Krox20, proneural genes (Xnrgn1, neuroD) and a neural differentiation gene (n-tubulin) is repressed in foxD5a-expressing cells. These results indicate that foxD5a maintains an undifferentiated neural ectoderm after neural induction. Expression of foxD5a constructs fused with the engrailed repressor domain or with the VP16 activation domain demonstrates that FoxD5a acts as a transcriptional repressor in axis formation and neural plate expansion. Deletion constructs indicate that this activity requires the C-terminal domain of the protein.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0012-1606
pubmed:author
pubmed:copyrightInfo
Copyright 2001 Academic Press.
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
232
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
439-57
pubmed:dateRevised
2009-11-3
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
foxD5a, a Xenopus winged helix gene, maintains an immature neural ectoderm via transcriptional repression that is dependent on the C-terminal domain.
pubmed:affiliation
Department of Anatomy and Cell Biology, The George Washington University Medical Center, Washington, DC 20037, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.