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Marta Florio,
Ketty Leto,
Luca Muzio,
Andrea Tinterri, Aurora Badaloni,
Laura Croci,
Paola Zordan,
Valeria Barili,
Ilaria Albieri,
François Guillemot,
Ferdinando Rossi,
G Giacomo Consalez
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ABSTRACT: By serving as the sole output of the cerebellar cortex, integrating a myriad of afferent stimuli, Purkinje cells (PCs) constitute the principal neuron in cerebellar circuits. Several neurodegenerative cerebellar ataxias feature a selective cell-autonomous loss of PCs, warranting the development of regenerative strategies. To date, very little is known as to the regulatory cascades controlling PC development. During central nervous system development, the proneural gene neurogenin 2 (Neurog2) contributes to many distinct neuronal types by specifying their fate and/or dictating development of their morphological features. By analyzing a mouse knock-in line expressing Cre recombinase under the control of Neurog2 cis-acting sequences we show that, in the cerebellar primordium, Neurog2 is expressed by cycling progenitors cell-autonomously fated to become PCs, even when transplanted heterochronically. During cerebellar development, Neurog2 is expressed in G1 phase by progenitors poised to exit the cell cycle. We demonstrate that, in the absence of Neurog2, both cell-cycle progression and neuronal output are significantly affected, leading to an overall reduction of the mature cerebellar volume. Although PC fate identity is correctly specified, the maturation of their dendritic arbor is severely affected in the absence of Neurog2, as null PCs develop stunted and poorly branched dendrites, a defect evident from the early stages of dendritogenesis. Thus, Neurog2 represents a key regulator of PC development and maturation.
Development 07/2012; 139(13):2308-20. · 6.60 Impact Factor
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ABSTRACT: Zinc finger protein 423 encodes a 30 Zn-finger transcription factor involved in cerebellar and olfactory development. ZFP423 is a known interactor of SMAD1-SMAD4 and of Collier/Olf-1/EBF proteins, and acts as a modifier of retinoic acid-induced differentiation. In the present article, we show that ZFP423 interacts with the Notch1 intracellular domain in mammalian cell lines and in Xenopus neurula embryos, to activate the expression of the Notch1 target Hes5/ESR1. This effect is antagonized by EBF transcription factors, both in cultured cells and in Xenopus embryos, and amplified in vitro by BMP4, suggesting that ZFP423 acts to integrate BMP and Notch signaling, selectively promoting their convergence onto the Hes5 gene promoter.
Journal of Biological Chemistry 10/2010; 285(40):30814-24. · 4.77 Impact Factor
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Ilaria Albieri,
Marco Onorati,
Giovanna Calabrese,
Alessia Moiana,
Daniele Biasci, Aurora Badaloni,
Stefano Camnasio,
Dimitrios Spiliotopoulos,
Zoltán Ivics,
Elena Cattaneo,
G Giacomo Consalez
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ABSTRACT: We describe the use of DNA transposons as tools for carrying out functional screenings in murine embryonic stem (ES) cell-derived neural stem (NS) cells. NS cells are a new type of stem cells featuring radial glial properties, that undergoes symmetric cell division for an indefinite number of passages, expanding as a monolayer. In this model, the previously unreported Sleeping Beauty transposase M3A achieves an optimal blend of clone generation efficiency and low redundancy of integrations per clone, compared to the SB100X Sleeping Beauty variant and to the piggyBac transposon. The technology described here makes it possible to randomly trap genes in the NS cell genome and modify their expression or tag them with fluorescent markers and selectable genes, allowing recombinant cells to be isolated and expanded clonally. This approach will facilitate the identification of novel determinants of stem cell biology and neural cell fate specification in NS cells.
Journal of biotechnology 10/2010; 150(1):11-21. · 2.88 Impact Factor
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ABSTRACT: Zinc finger protein 423 encodes a 30 Zn-finger transcription factor involved in cerebellar and olfactory development. ZFP423
is a known interactor of SMAD1-SMAD4 and of Collier/Olf-1/EBF proteins, and acts as a modifier of retinoic acid-induced differentiation.
In the present article, we show that ZFP423 interacts with the Notch1 intracellular domain in mammalian cell lines and in
Xenopus neurula embryos, to activate the expression of the Notch1 target Hes5/ESR1. This effect is antagonized by EBF transcription factors, both in cultured cells and in Xenopus embryos, and amplified in vitro by BMP4, suggesting that ZFP423 acts to integrate BMP and Notch signaling, selectively promoting their convergence onto the
Hes5 gene promoter.
Journal of Biological Chemistry 09/2010; 285(40):30814-30824. · 4.77 Impact Factor
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ABSTRACT: Cerebellar unipolar brush cells (UBCs) are glutamatergic interneurons of the granular layer. Previous studies have identified three distinct UBC subsets in the mouse cerebellar cortex: one expressing the calcium-binding protein calretinin (CR), a second expressing both the metabotropic glutamate receptor (mGluR)1alpha and phospholipase C(PLC)beta4, and a third expressing PLCbeta4 but not mGluR1alpha. We have investigated UBC topography in two strains of mutant mice: early B-cell factor 2 (Ebf2) null and scrambler. In Ebf2 null mice Purkinje cell topography is disrupted due to Purkinje cell death and ectopic gene expression. The topography of all three classes of UBCs is also abnormal: the CR(+) UBCs, which are normally aligned with zebrin II stripes, become homogeneously distributed; the numerical density of mGluRlalpha(+) UBCs is increased; and many PLCbeta4(+) UBCs are located ectopically. The UBC ectopia is not a cell-intrinsic action of the Ebf2 gene-analysis of the constitutive expression of a beta-galactoside reporter under the control of the Ebf2 promoter reveals no Ebf2 expression in UBCs at any stage of cerebellar development. In scrambler (Dab1(scm)), most Purkinje cells are ectopic but nevertheless have normal adult gene expression patterns. In scrambler, UBCs associate with specific ectopic Purkinje cell clusters. Finally, similar associations with specific Purkinje cell clusters are seen during normal cerebellar development. These data suggest that UBCs become regionally restricted during development through a non-cell-autonomous mechanism involving embryonic interactions with different Purkinje cell subtypes.
Neuroscience 10/2009; 164(4):1496-508. · 3.38 Impact Factor
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ABSTRACT: Improved and modular tools are needed for the neuroanatomical dissection of CNS axonal tracts, and to study the cell-intrinsic and cell-extrinsic cues that govern their assembly and plasticity. Here we describe a general purpose transgenic tracer that can be used to visualize axonal tracts and synaptic terminals in any region of the embryonic neural tube or postnatal CNS, on any wild type or mutant genetic background. The construct permits CRE-inducible expression of a dicistronic axonal marker encoding two surface reporter proteins: a farnesylated GFP and the human Placental Alkaline Phosphatase (PLAP). Both proteins localize alongside the neuronal surface, permitting the concomitant detection of cell body, neurites, and presynaptic and postsynaptic sites in the same neuron. This provides a CRE-inducible dual system for imaging neural circuits in vivo, and to study their assembly and remodeling in cultured neurons, neural stem cells, and tissue explants derived from the reporter line. Unlike existing lines, this reporter does not encode a ubiquitously expressed, floxable LacZ gene, permitting the simultaneous analysis of beta galactosidase activity in mutant lines.
genesis 07/2007; 45(6):405-12. · 2.53 Impact Factor
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ABSTRACT: Through in vivo loss-of-function studies, vertebrate members of the Male abnormal 21 (mab-21) gene family have been implicated in gastrulation, neural tube formation and eye morphogenesis. Despite mounting evidence of their considerable importance in development, the biochemical properties and nature of MAB-21 proteins have remained strikingly elusive. In addition, genetic studies conducted in C. elegans have established that in double mutants mab-21 is epistatic to genes encoding various members of a Transforming Growth Factor beta (TGF-beta) signaling pathway involved in the formation of male-specific sensory organs.
Through a gain-of-function approach, we analyze the interaction of Mab21l2 with a TGF-beta signaling pathway in early vertebrate development. We show that the vertebrate mab-21 homolog Mab21l2 antagonizes the effects of Bone Morphogenetic Protein 4 (BMP4) overexpression in vivo, rescuing the dorsal axis and restoring wild-type distribution of Chordin and Xvent2 transcripts in Xenopus gastrulae. We show that MAB21L2 immunoprecipitates in vivo with the BMP4 effector SMAD1, whilst in vitro it binds SMAD1 and the SMAD1-SMAD4 complex. Finally, when targeted to an heterologous promoter, MAB21L2 acts as a transcriptional repressor.
Our results provide the first biochemical and cellular foundation for future functional studies of mab-21 genes in normal neural development and its pathological disturbances.
BMC Cell Biology 02/2004; 5(1):48. · 2.59 Impact Factor
