The Mnx homeobox gene class defined by HB9 , MNR2 and amphioxus AmphiMnx

Ferrier, David; Brooke, Nina M.; Panopoulou, Georgia; Holland, Peter W.H.

doi:10.1007/s004270000124

Cited by 52 publications

(49 citation statements)

References 16 publications

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“…By the end of neurulation, the expression had resolved into a reiterated series of dorsal and ventral neural cord cells and also appeared in some cells of the cerebral vesicle. This is similar to several other amphioxus genes proposed to have roles in regulating neuronal patterning and differentiation, for example, islet and Mnx, although is not identical to any previously characterised gene (Ferrier et al, 2001;Jackman et al, 2000). Specifically, ventral cells expressing AmphiCoe lie in a similar position to cells expressing islet and Mnx; however, more dorsal cells express AmphiCoe than have been shown to express islet ( Jackman and Kimmel 2002).…”

Section: Expression Of Amphicoe In the Cnsmentioning

confidence: 51%

Expression of AmphiCoe, an amphioxus COE/EBF gene, in the developing central nervous system and epidermal sensory neurons

Mazet

Masood

Luke

et al. 2004

Genesis

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The COE/EBF gene family marks a subset of prospective neurons in the vertebrate central and peripheral nervous system, including neurons deriving from some ectodermal placodes. Since placodes are often considered unique to vertebrates, we have characterised an amphioxus COE/EBF gene with the aim of using it as a marker to examine the timing and location of peripheral neuron differentiation. A single COE/EBF family member, AmphiCoe, was isolated from the amphioxus Branchiostoma floridae. AmphiCoe lies basal to the vertebrate COE/EBF genes in molecular phylogenetic analysis, suggesting that the duplications that formed the vertebrate COE/EBF family were specific to the vertebrate lineage. AmphiCoe is expressed in the central nervous system and in a small number of scattered ectodermal cells on the flanks of neurulae stage embryos. These cells become at least largely recessed beneath the ectoderm. Scanning electron microscopy was used to examine embryos in which the ectoderm had been partially peeled away. This revealed that these cells have neuronal morphology, and we infer that they are the precursors of epidermal primary sensory neurons. These characters lead us to suggest that differentiation of some ectodermal cells into sensory neurons with a tendency to sink beneath the embryonic surface represents a primitive feature that has become incorporated into placodes during vertebrate evolution.

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Section: Expression Of Amphicoe In the Cnsmentioning

confidence: 51%

Expression of AmphiCoe, an amphioxus COE/EBF gene, in the developing central nervous system and epidermal sensory neurons

Mazet

Masood

Luke

et al. 2004

Genesis

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“…The expression of Hb9 in motoneurons is evolutionarily conserved in many species ranging from humans to Drosophila (Arber et al, 1999;Broihier and Skeath, 2002;Ferrier et al, 2001;Ross et al, 1998;Saha et al, 1997;Thaler et al, 1999;Vult von Steyern et al, 1999). Therefore, we compared the nucleotide sequence of the Hb9 promoter region from mouse and human to identify regions of conservation that might be involved in regulating gene expression.…”

Section: Resultsmentioning

confidence: 99%

Analysis of embryonic motoneuron gene regulation: derepression of general activators function in concert with enhancer factors

et al. 2004

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The underlying transcriptional mechanisms that establish the proper spatial and temporal pattern of gene expression required for specifying neuronal fate are poorly defined. We have characterized how the Hb9 gene is expressed in developing motoneurons in order to understand how transcription is directed to specific cells within the developing CNS. We found that non-specific general-activator proteins such as E2F and Sp1 are capable of driving widespread low level transcription of Hb9 in many cell types throughout the neural tube; however, their activity is modulated by specific repressor and activator complexes. The general-activators of Hb9 are suppressed from triggering inappropriate transcription by repressor proteins Irx3 and Nkx2.2. High level motoneuron expression is achieved by assembling an enhancesome on a compact evolutionarily-conserved segment of Hb9located from –7096 to –6896. The ensemble of LIM-HD and bHLH proteins that interact with this enhancer change as motoneuron development progresses, facilitating both the activation and maintenance of Hb9expression in developing and mature motoneurons. These findings provide direct support for the derepression model of gene regulation and cell fate specification in the neural tube, as well as establishing a role for enhancers in targeting gene expression to a single neuronal subtype in the spinal cord.

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“…9, 10). MNR2 is a member of an evolutionarily conserved subgroup of Mnx class proteins; it is strongly expressed in the mm but more weakly in the lm (Ferrier et al, 2001; Fig. 9A).…”

Section: Differential Expression Patterns Of Delta-pcdhs In Motor Poolsmentioning

confidence: 98%

Expression of delta‐protocadherins in the spinal cord of the chicken embryo

Lin

Wang

Redies

2012

J of Comparative Neurology

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Protocadherins constitute the largest subfamily of cadherin genes and are widely expressed in the nervous system. In the present study, we cloned eight members of the delta-protocadherin subfamily of cadherins (Pcdh1, Pcdh7, Pcdh8, Pcdh9, Pcdh10, Pcdh17, Pcdh18, and Pcdh19) from the chicken, and investigated their expression in the developing chicken spinal cord by in situ hybridization. Our results showed that each of the investigated delta-protocadherins exhibits a spatially restricted and temporally regulated pattern of expression. Pcdh1, Pcdh8, Pcdh18, and Pcdh19 are expressed in restricted dorsoventral domains of the neuroepithelial layer at early developmental stages (E2.5–E4). In the differentiating mantle layer, specific expression profiles are observed for all eight delta-protocadherins along the dorsoventral, mediolateral, and rostrocaudal dimensions at intermediate stages of development (E6–E10). Expression profiles are especially diverse in the motor column, where different pools of motor neurons exhibit signal for subsets of delta-protocadherins. In the dorsal root ganglion, subpopulations of cells express combinations of Pcdh1, Pcdh7, Pcdh8, Pcdh9, Pcdh10, and Pcdh17. The ventral boundary cap cells are positive for Pcdh7, Pcdh9, and Pcdh10. Signals for Pcdh8, Pcdh18, and Pcdh19 are found in the meninges. Surrounding tissues, such as the notochord, dermomyotome, and sclerotome also exhibit differential expression patterns. The highly regulated spatiotemporal expression patterns of delta-protocadherins suggest that they have multiple and diverse functions during development of the spinal cord and its surrounding tissues.

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The Mnx homeobox gene class defined by HB9 , MNR2 and amphioxus AmphiMnx

Cited by 52 publications

References 16 publications

Expression of AmphiCoe, an amphioxus COE/EBF gene, in the developing central nervous system and epidermal sensory neurons

Expression of AmphiCoe, an amphioxus COE/EBF gene, in the developing central nervous system and epidermal sensory neurons

Analysis of embryonic motoneuron gene regulation: derepression of general activators function in concert with enhancer factors

Expression of delta‐protocadherins in the spinal cord of the chicken embryo

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