Regulatory gene expression boundaries demarcate sites of neuronal differentiation in the embryonic zebrafish forebrain

Macdonald, Rachel; Xu, Qiling; Barth, Katrin; Mikkola, Ingvild; Holder, Nigel; Fjose, Anders; Krauß, Stefan; Wilson, Stephen W.

doi:10.1016/0896-6273(94)90044-2

Cited by 221 publications

(184 citation statements)

References 54 publications

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“…The location of the nMLF has been mapped relative to the expression of several molecular markers in the 24 hpf zebrafish brain (Macdonald et al, 1994;Barth and Wilson, 1995;Hauptmann and Gerster, 2000;Hjorth and Key, 2001). It lies at the interface of shh and nkx2.2 expression, overlapping the caudal boundary of pax6.1 expression.…”

Section: Resultsmentioning

confidence: 99%

“…At early stages, the borders of expression of several patterning genes often reflect axonal routes (Wilson et al, 1993Macdonald et al, 1994). Detailed expression studies and functional analyses support a direct or indirect role for some of these patterning genes in the formation or the refinement of axon trajectories Mastick et al, 1997;Ba-Charvet et al, 1998;Bertuzzi et al, 1999;Hallonet et al, 1999;Hjorth and Key, 2001).…”

Section: Introductionmentioning

confidence: 99%

“…Transition zones in the regions of expression of different combinations of patterning genes also correlate with the position of the first neuronal clusters. For example, the differentiating neuron cell bodies of the MLF and the posterior commissure (nPC) overlap with the anteroposterior (AP) transition between the mesencephalon and caudal prosencephalon (later on referred to as fore/mid boundary), as defined by anatomic and molecular landmarks (Macdonald et al, 1994;Mastick and Easter, 1996). Similarly, the nMLF lies at the dorsal boundary of shh expression along the dorsoventral (DV) axis (Macdonald et al, 1994;Barth and Wilson, 1995).…”

Section: Introductionmentioning

confidence: 99%

“…For example, the differentiating neuron cell bodies of the MLF and the posterior commissure (nPC) overlap with the anteroposterior (AP) transition between the mesencephalon and caudal prosencephalon (later on referred to as fore/mid boundary), as defined by anatomic and molecular landmarks (Macdonald et al, 1994;Mastick and Easter, 1996). Similarly, the nMLF lies at the dorsal boundary of shh expression along the dorsoventral (DV) axis (Macdonald et al, 1994;Barth and Wilson, 1995). Based on these observations, it has been proposed that the stereotypical arrangement of the first neuronal clusters responds to the intersection of distinct positional identities.…”

Section: Introductionmentioning

confidence: 99%

“…The ontogeny of the nMLF/nPC has been precisely mapped. AChE activity or immunocytochemistry against HNK1 or acetylated-tubulin revealed the first nMLF cell bodies around 16 hr postfertilization (hpf), at the junction of the fore-(pax6.1-positive; Krauss et al, 1991;Pü schel et al, 1992) and midbrain (eng-positive; Ekker et al, 1992) patterning systems along the AP axis, and along the dorsal and ventral edges of shh and nkx2.2 expression, respectively, along the DV axis (Macdonald et al, 1994;Barth and Wilson, 1995;Hjorth and Key, 2001). nPC cell bodies are detectable from 18 hpf onward.…”

Section: Introductionmentioning

confidence: 99%

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Selective control of neuronal cluster size at the forebrain/midbrain boundary by signaling from the prechordal plate

Tallafuß

Adolf

Bally‐Cuif

2003

Developmental Dynamics

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Within the vertebrate embryonic neural plate, the first neuronal clusters often differentiate at the border of patterning identities. Whether the information inherent in the intersection of patterning identities alone controls all aspects of neuronal cluster development (location, identity, and size) is unknown. Here, we focus on the cluster of the medial longitudinal fascicle (nMLF) and posterior commissure (nPC), located at the forebrain/midbrain (fore/mid) boundary, to address this issue. We first identify expression of the transcription factor Six3 as a common and distinct molecular signature of nMLF and nPC neurons in zebrafish, and we use this marker to monitor mechanisms controlling the location and number of nMLF/nPC neurons. We demonstrate that six3 expression is induced at the fore/mid boundary in pax2.1/no-isthmus and smoothened/slow muscle omitted mutants, where identities adjacent to the six3 cluster are altered; however, in these mutants, the subpopulation of six3-positive cells located within the mispatterned territory is reduced. These results show that induction of the six3 cluster is triggered by the information derived from the intersection in patterning identities alone, whereas correct cluster size depends, in a modular manner, on the identities themselves. The size of the six3 cluster is also controlled independently of neural tube patterning: we demonstrate that the prechordal plate (PCP) is impaired in mixer/bonnie and clyde mutants and that this phenotype secondarily results in an increased production of six3-positive cells at the fore/mid boundary, without correlatively affecting patterning in this area. Thus, a signaling process originating from the PCP distinguishes between neural patterning and the control of six3 cluster size at the fore/mid junction in vivo. Together, our results suggest that a combination of patterning-related and -unrelated mechanisms specifically controls the size of individual early neuronal clusters within the anterior neural plate. Developmental Dynamics 227:524 -535, 2003.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Selective control of neuronal cluster size at the forebrain/midbrain boundary by signaling from the prechordal plate

Tallafuß

Adolf

Bally‐Cuif

2003

Developmental Dynamics

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Expression of the cell adhesion molecule axonin-1 in neuromeres of the chicken diencephalon

1997

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Axonin-1/TAG-1, a member of the immunoglobulin (Ig) superfamily of adhesion molecules, has been shown to be selectively expressed by a subset of neurons and fiber tracts in the developing nervous system of vertebrates. Axonin-1/TAG-1 is thought to play a role in the outgrowth, guidance, and fasciculation of neurites. In the present study, we map the expression of axonin-1 in the diencephalon of the chicken brain at early and intermediate stages of development [2-8 days of incubation; embryonic day (E)2-E8] by immunohistochemical methods. Results show that axonin-1 is first expressed at about E2.5 by postmitotic neurons scattered throughout most of the diencephalon. During the neuromeric stage of brain development (about E3-E5), axonin-1+ nerve cell bodies are predominantly found in two neuromeric subdivisions: 1) in the alar plate of the precommissural pretectum and dorsal thalamus and 2) in the posterior preoptic region of the hypothalamus. The axonin-1+ fiber bundles emerging from these areas grow across segmental boundaries. For example, axonin-1+ neurites originating in the dorsal thalamus cross the zona limitans intrathalamica at a right angle to project to the striatum. Later, the axonin-1+ neuromere areas give rise to particular axonin-1+ gray and white matter structures. Most of these structures correspond to the structures described to express TAG-1 in rodents. In conclusion, axonin-1 can be used as a marker to study aspects of the transition from the early neuromeric structure to the mature anatomy of the chicken brain.

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Sequence and expression of glutamic acid decarboxylase isoforms in the developing zebrafish

1998

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We describe the isolation two glutamic acid decarboxylase (GAD) cDNAs from zebrafish with over 84% identity to human GAD65 and GAD67. In situ hybridization studies revealed that both GAD65 and GAD67 were expressed in the early zebrafish embryo during the period of axonogenesis, suggesting a role for GABA prior to synapse formation. Both GAD genes were detected in the telencephalon, in the nucleus of the medial longitudinal fasciculus in the midbrain, and at the border regions of the rhombomeres in the rostral hindbrain. In the caudal hindbrain, only GAD67 was detected (in neurons with large-caliber axons). In the spinal cord, both GAD genes were detected in dorsal longitudinal neurons, commissural secondary ascending neurons, ventral longitudinal neurons, and Kolmer-Agduhr neurons. Immunohistochemistry for gamma-aminobutyric acid (GABA) revealed that GABA is produced at all sites of GAD expression, including the novel cells in the caudal hindbrain. These results are discussed in the context of the hindbrain circuitry that supports the escape response. We conclude that fish, like mammals, have two GAD genes. The zebrafish GAD65 and GAD67 are present in identified neurons in the forebrain, midbrain, hindbrain, and spinal cord, and they catalyze the production of GABA in the developing embryo.

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Regulatory gene expression boundaries demarcate sites of neuronal differentiation in the embryonic zebrafish forebrain

Cited by 221 publications

References 54 publications

Selective control of neuronal cluster size at the forebrain/midbrain boundary by signaling from the prechordal plate

Selective control of neuronal cluster size at the forebrain/midbrain boundary by signaling from the prechordal plate

Expression of the cell adhesion molecule axonin-1 in neuromeres of the chicken diencephalon

Sequence and expression of glutamic acid decarboxylase isoforms in the developing zebrafish

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