Morpholino‐induced knockdown of Fgf8 efficiently phenocopies the acerebellar (ACE) phenotype

Araki, Isato; Brand, Michael

doi:10.1002/gene.1054

Cited by 25 publications

(23 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is therefore conceivable that upon displaying functional Fgf8 to otx2-expressing ace mutant tectal cells, the repressive genetic interactions (MartinezBarbera et al, 2001) playing a role during normal MHB maintenance are re-established, accounting for the reversal of the tectal morphology and identity on the operated side in ace embryos. Conversely, in ace mutants where functional Fgf8 signaling is absent (Reifers et al, 1998;Araki and Brand, 2001), otx2 transcripts are not repressed, causing a strong similarity to rostral mesencephalic regions experiencing putatively low or no Fgf8 signal as a function of the distance from the emitting source. Consequently, the mesencephalic/tectal differentiation program is executed in place of the metencephalic alar plate in ace mutants.…”

Section: Possible Molecular Mechanisms Underlying the Isthmus-to-midbmentioning

confidence: 99%

Isthmus-to-midbrain transformation in the absence of midbrain-hindbrain organizer activity

et al. 2003

Self Cite

View full text Add to dashboard Cite

In zebrafish acerebellar (ace) embryos, because of a point mutation in fgf8, the isthmic constriction containing the midbrain-hindbrain boundary (MHB) organizer fails to form. The mutants lack cerebellar development by morphological criteria, and they appear to have an enlarged tectum, showing no obvious reduction in the tissue mass at the dorsal mesencephalic/metencephalic alar plate. To reveal the molecular identity of the tissues located at equivalent rostrocaudal positions along the neuraxis as the isthmic and cerebellar primordia in wild-types, we undertook a detailed analysis of ace embryos. In ace mutants, the appearance of forebrain and midbrain specific marker genes (otx2, dmbx1, wnt4) in the caudal tectal enlargement reveals a marked rostralized gene expression profile during early somitogenesis, followed by the lack of early and late cerebellar-specific gene expression (zath1/atoh1, gap43,tag1/cntn2, neurod, zebrin II). The Locus coeruleus(LC) derived from rostral rhombomere 1 is also absent in the mutants. A new interface between otx2 and epha4a suggests that the rostralization stops at the caudal part of rhombomere 1. The mesencephalic basal plate is also affected in the mutant embryos, as indicated by the caudal expansion of the diencephalic expression domains of epha4a,zash1b/ashb, gap43 and tag1/cntn2, and by the dramatic reduction of twhh expression. No marked differences are seen in cell proliferation and apoptotic patterns around the time the rostralization of gene expression becomes evident in the mutants. Therefore,locally distinct cell proliferation and cell death is unlikely to be the cause of the fate alteration of the isthmic and cerebellar primordia in the mutants. Dil cell-lineage labeling of isthmic primordial cells reveals that cells, at the location equivalent of the wild-type MHB, give rise to caudal tectum in ace embryos. This suggests that a caudalto-rostral transformation leads to the tectal expansion in the mutants. Fgf8-coated beads are able to rescue morphological MHB formation, and elicit the normal molecular identity of the isthmic and cerebellar primordium in ace embryos. Taken together, our analysis reveals that cells of the isthmic and cerebellar primordia acquire a more rostral, tectal identity in the absence of the functional MHB organizer signal Fgf8.

show abstract

Section: Possible Molecular Mechanisms Underlying the Isthmus-to-midbmentioning

confidence: 99%

Isthmus-to-midbrain transformation in the absence of midbrain-hindbrain organizer activity

et al. 2003

Self Cite

View full text Add to dashboard Cite

show abstract

“…For transient knock-down of gene expression, Morpholinoantisense oligomers (Morpholinos; MO; by GeneTools) were prepared targeting eng2 and eng3 (Scholpp and Brand, 2001), fgf3 (Raible and Brand, 2001), fgf4 and fgf8 (Araki and Brand, 2001) by dissolving in 5 mM HEPES-buffer with 0.2% Phenol Red. Morpholinos were injected into the yolk cell close to the blastomeres between the oneand eight-cell stages at a concentration of 4 ng/nl.…”

Section: Injectionsmentioning

confidence: 99%

“…(Araki and Brand, 2001;Raible and Brand, 2001). The embryos were injected with 4 ng of MO and showed genespecific defects.…”

Section: Fgf8 and Engrailed Act In A Synergistic Fashion To Position mentioning

confidence: 99%

Engrailed and Fgf8 act synergistically to maintain the boundary between diencephalon and mesencephalon

2003

Self Cite

View full text Add to dashboard Cite

show abstract

“…Thus, the ace mutant provides important evidence that specific Fgf proteins are not only expressed but required during heart formation (Reifers et al, 2000). Morpholino knockdown of fgf8 mimics the ace phenotype, suggesting that the use of morpholinos to simultaneously inhibit other members of the zebrafish Fgf family alone or simultaneously could be used to investigate their roles in vertebrate heart development further (Araki and Brand, 2001). pan and fog mutants have a defect in the generation of myocardial cells that results from mutations in the genes encoding the transcription elongation factors Spt6 and Spt5, respectively (Guo et al, 2000;Keegan et al, 2002).…”

Section: Atrium And/or Ventricle Defectsmentioning

confidence: 99%

Modeling human hematopoietic and cardiovascular diseases in zebrafish

North

Zon

2003

Developmental Dynamics

View full text Add to dashboard Cite

Zebrafish have emerged as a useful vertebrate model system in which unbiased large-scale screens have revealed hundreds of mutations affecting vertebrate development. Many zebrafish mutants closely resemble known human disorders, thus providing intriguing prospects for uncovering the genetic basis of human diseases and for the development of pharmacologic agents that inhibit or correct the progression of developmental disorders. The rapid pace of advances in genomic sequencing and map construction, in addition to morpholino targeting and transgenic techniques, have facilitated the identification and analysis of genes associated with zebrafish mutants, thus promoting the development of zebrafish as a model for human disorders. This review aims to illustrate how the zebrafish has been used to identify unknown genes, to assign function to known genes, and to delineate genetic pathways, all contributing valuable leads toward understanding human pathophysiology. Developmental Dynamics 228:568 -583, 2003.

show abstract

Morpholino‐induced knockdown of Fgf8 efficiently phenocopies the acerebellar (ACE) phenotype

Cited by 25 publications

References 8 publications

Isthmus-to-midbrain transformation in the absence of midbrain-hindbrain organizer activity

Isthmus-to-midbrain transformation in the absence of midbrain-hindbrain organizer activity

Engrailed and Fgf8 act synergistically to maintain the boundary between diencephalon and mesencephalon

Modeling human hematopoietic and cardiovascular diseases in zebrafish

Contact Info

Product

Resources

About