Abstract
Dbx homeodomain proteins are important for spinal cord dorsal/ventral patterning and the production of multiple spinal cord cell types. We have examined the regulation and function of Dbx genes in the zebrafish. We report that Hedgehog signaling is not required for the induction or maintenance of these genes; in the absence of Hedgehog signaling, dbx1a/1b/2 are expanded ventrally with concomitant increases in postmitotic neurons that differentiate from this domain. Also, we find that retinoic acid signaling is not required for the induction of Dbx expression. Furthermore, we are the first to report that knockdown of Dbx1 function causes a dorsal expansion of nkx6.2, which is thought to be the cross-repressive partner of Dbx1 in mouse. Our data confirm that the dbx1a/1b/2 domain in zebrafish spinal cord development behaves similarly to amniotes, while extending knowledge of Dbx1 function in spinal cord patterning.
2007 Wiley-Liss, Inc
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Animals
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Base Sequence
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Body Patterning / genetics
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Embryonic Stem Cells / cytology
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Embryonic Stem Cells / metabolism
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Gene Expression Regulation, Developmental
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Genes, Homeobox*
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Hedgehog Proteins / genetics
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Hedgehog Proteins / metabolism
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Homeodomain Proteins / antagonists & inhibitors
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Homeodomain Proteins / genetics
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Neuroglia / cytology
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Neuroglia / metabolism
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Neurons / cytology
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Neurons / metabolism
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Oligodeoxyribonucleotides, Antisense / genetics
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Signal Transduction
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Spinal Cord / cytology
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Spinal Cord / embryology*
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Spinal Cord / metabolism*
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Transcription Factors / antagonists & inhibitors
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Transcription Factors / genetics
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Tretinoin / metabolism
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Zebrafish / embryology*
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Zebrafish / genetics*
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Zebrafish / metabolism
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Zebrafish Proteins / antagonists & inhibitors
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Zebrafish Proteins / genetics
Substances
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Hedgehog Proteins
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Homeodomain Proteins
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Oligodeoxyribonucleotides, Antisense
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Transcription Factors
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Zebrafish Proteins
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dbx1a protein, zebrafish
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dbx1b protein, zebrafish
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dbx2 protein, zebrafish
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Tretinoin