Aixa V. Morales

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The Snail zinc-finger transcription factors trigger epithelial-mesenchymal transitions (EMTs), endowing epithelial cells with migratory and invasive properties during both embryonic development and tumor progression. During EMT, Snail provokes the loss of epithelial markers, as well as changes in cell shape and the expression of mesenchymal markers. Here,(More)
A molecular oscillator regulates the pace of vertebrate segmentation. Here, we show that the oscillator (clock) controls cyclic initiation of transcription in the unsegmented presomitic mesoderm (PSM). We identify an evolutionarily conserved 2.3 kb region in the murine Lunatic fringe (Lfng) promoter that drives periodic expression in the PSM. This region(More)
Coordination between functionally related adjacent tissues is essential during development. For example, formation of trunk neural crest cells (NCCs) is highly influenced by the adjacent mesoderm, but the molecular mechanism involved is not well understood. As part of this mechanism, fibroblast growth factor (FGF) and retinoic acid (RA) mesodermal gradients(More)
Genes of the SOX family of high-mobility group transcription factors are essential during nervous system development. In this study, we show that SOX5 is expressed by neural progenitors in the chick spinal cord and is turned off as differentiation proceeds. The overexpression of SOX5 in neural progenitors causes premature cell cycle exit and prevents(More)
The characterization of (pro)insulin as an early embryonic growth factor requires demonstration of its expression and cellular effects in vivo. By in situ hybridization, we found widespread preproinsulin transcripts in the chick embryo throughout gastrulation and neurulation, before the beginning of preproinsulin-like growth factor I expression and(More)
A prevalent developmental mechanism for the assignment of cell identities is the production of spatiotemporal concentration gradients of extracellular signaling molecules that are interpreted by the responding cells. One of such signaling systems is the Shh gradient that controls neuronal subtype identity in the ventral spinal cord. Using loss and gain of(More)
The development of the neural crest up to the stage where they leave the neural tube can be observed as a series of concatenated but independent events that involve dorsalization of the neural plate/neural tube, neural crest induction, segregation and stabilization, epithelial to mesenchymal transition and delamination. During all these processes, the(More)
The specific actions of insulin-like growth factor-I (IGF-I) and the role of brain-derived IGF-I during hippocampal neurogenesis have not been fully defined. To address the influence of IGF-I on the stages of hippocampal neurogenesis, we studied a postnatal/adult global Igf-I knockout (KO) mice (Igf-I(-/-) ) and a nervous system Igf-I conditional KO(More)
Despite the absence of a pancreas, which develops between embryonic day 3 (E3) to E4, previous studies showed that insulin receptors are widely expressed in chicken embryos from the blastoderm stage (unincubated embryo, E0) through gastrulation (E0.5-E1), neurulation (E1.5-E2), and organogenesis. We now characterize prepancreatic preproinsulin gene(More)