A role for FGF-8 in the dorsoventral patterning of the zebrafish gastrula.
Signals released from Spemann's organizer, together with ventralizing factors such as BMPs, are necessary to pattern the dorsoventral axis of the vertebrate embryo. We report that a member of the FGF family, fgf-8, not secreted by the axial mesoderm but expressed in a dorsoventral gradient at the margin of the zebrafish gastrula, also contributes to the establishment of the dorsoventral axis of the embryo. Ectopic expression of FGF-8 leads to the expansion of dorsolateral derivatives at the expense of ventral and posterior domains. Moreover, FGF-8 displays some organizer properties as it induces the formation of a partial secondary axis in the absence of factors released from Spemann's organizer territory. Analysis of its interaction with the ventralizing factors, BMPs, reveals that overexpression of FGF-8 inhibits the expression of these factors in the ventral part of the embryo as early as blastula stage, suggesting that FGF-8 acts upstream of BMP2 and BMP4. We conclude that FGF-8 is involved in defining dorsoventral identity and is an important organizing factor responsible for specification of mesodermal and ectodermal dorsolateral territories of the zebrafish gastrula.
Fürthauer
M
M
Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, ULP, Illkirch, France.
Thisse
C
C
Thisse
B
B
D000595:Amino Acid Sequence; D000818:Animals; D001755:Blastocyst / Q000502:physiology; D019521:Body Patterning / Q000235:genetics*; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D004625:Embryo, Nonmammalian; D004627:Embryonic Induction / Q000235:genetics; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors; D005775:Gastrula / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D006133:Growth Substances / Q000502:physiology*; D008636:Mesencephalon / Q000196:embryology; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins
D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D006133:Growth Substances; D016212:Transforming Growth Factor beta; D029961:Zebrafish Proteins; C525813:bmp4 protein, zebrafish; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors