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Ulloa F.,Barcelona Institute for Research in Biomedicine | Marti E.,Institute Biologia Molecular Of Barcelona
Developmental Dynamics | Year: 2010

The spinal cord has been used as a model to dissect the mechanisms that govern the patterning of tissues during animal development, since the principles that rule the dorso-ventral patterning of the neural tube are applicable to other systems. Signals that determine the dorso-ventral axis of the spinal cord include Sonic hedgehog (Shh), acting as a bona fide morphogenetic signal to determine ventral progenitor identities, and members of the Bmp and the Wnt families, acting in the dorsal neural tube. Although Wnts have been initially recognized as important in proliferation of neural progenitor cells, their role in the dorso-ventral patterning has been controversial. In this review, we discuss recent reports that show an important contribution of the Wnt canonical pathway in dorso-ventral pattern formation. These data allow building a model by which the ventralizing activity of Shh is antagonized by Wnt activity through the expression of Gli3, a potent inhibitor of the Shh pathway. Therefore, antagonistic interactions between canonical Wnt, promoting dorsal identities, and Shh pathways, inducing ventral ones, would define the dorso-ventral patterning of the developing central nervous system. © 2009 Wiley-Liss, Inc.

Roca J.,Institute Biologia Molecular Of Barcelona
Chromosoma | Year: 2011

Virtually all processes of the genome biology affect or are affected by the torsional state of DNA. Torsional energy associated with an altered twist facilitates or hinders the melting of the double helix, its molecular interactions, and its spatial folding in the form of supercoils. Yet, understanding how the torsional state of DNA is modulated remains a challenging task due to the multiplicity of cellular factors involved in the generation, transmission, and dissipation of DNA twisting forces. Here, an overview of the implication of DNA topoisomerases, DNA revolving motors, and other DNA interactions that determine local levels of torsional stress in bacterial and eukaryotic chromosomes is provided. Particular emphasis is made on the experimental approaches being developed to assess the torsional state of intracellular DNA and its organization into topological domains. © Springer-Verlag 2011.

Estaras C.,Institute Biologia Molecular Of Barcelona
Development (Cambridge, England) | Year: 2012

Neural development requires crosstalk between signaling pathways and chromatin. In this study, we demonstrate that neurogenesis is promoted by an interplay between the TGFβ pathway and the H3K27me3 histone demethylase (HDM) JMJD3. Genome-wide analysis showed that JMJD3 is targeted to gene promoters by Smad3 in neural stem cells (NSCs) and is essential to activate TGFβ-responsive genes. In vivo experiments in chick spinal cord revealed that the generation of neurons promoted by Smad3 is dependent on JMJD3 HDM activity. Overall, these findings indicate that JMJD3 function is required for the TGFβ developmental program to proceed.

Roca J.,Institute Biologia Molecular Of Barcelona
Transcription | Year: 2011

Most genome transactions are favored by DNA (-) torsional stress, i.e. unconstrained unwinding or supercoiling of DNA. A question raised here is whether DNA (+) torsional stress, which precludes DNA unwinding, could be also relevant in gene regulation. Such DNA twist dynamics could be determined by chromatin architecture.

Lesage B.,Barcelona Institute for Research in Biomedicine | Gutierrez I.,Institute Biologia Molecular Of Barcelona | Marti E.,Institute Biologia Molecular Of Barcelona | Gonzalez C.,Barcelona Institute for Research in Biomedicine | Gonzalez C.,Catalan Institution for Research and Advanced Studies
Current Opinion in Genetics and Development | Year: 2010

Drosophila neuroblasts and mouse radial glial cells can divide asymmetrically to self-renew while producing differentiating daughter cells that contribute to brain growth. Intense research activity in the past few years has started to unveil some of the processes that govern asymmetric division in these two cell types. Here we discuss the case of centrosome asymmetry and the contribution of spindle orientation and non-spindle-related centrosome functions. Although still fragmentary, the emerging picture suggests that both notable parallelisms and striking differences apply. © 2010 Elsevier Ltd.

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