<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "A Wif1 mediated feedback loop suppresses\r\npremature Wnt signaling in nascent habenular\r\nneurons"^^ . "Precise temporal and spatial control of cell signaling processes is pivotal for\r\nembryonic development. A vast number of secreted signaling molecules such as Wnt\r\nligands travel between cells and tissues and influence their fate. If they are to induce a\r\nsignaling cascade depends on various control mechanisms of potential target cells.\r\nThese can include the temporal expression control of pathway components or the\r\ngeneration of signaling agonisers or antagonisers. Control of Wnt/beta-catenin\r\nsignaling is important for the establishment of left- rigt (l-r) neuronal asymmetries of\r\nthe evolutionarily conserved habenulae in the vertebrate dorsal diencephalon. During\r\nneurogenesis, this pathway is activated only when habenular precursor cells become\r\npost-mitotic, although Wnt ligands secreted by the adjacent mid-diencephalic\r\norganizer (MDO) surround these cells much earlier. The underlying control\r\nmechanism and its purpose have remained unexplored. We find that Wnt signaling is\r\nindeed initially inhibited in habenular precursors and that this is required for\r\nhabenular neurons to subsequently adopt different neuronal fates. Indeed, premature\r\ninduction of the pathway critically delays neuronal differentiation which ultimately\r\nlead to precursor differentiation into only one out of two neuron types of the\r\nhabenulae on both sides of the brain. We further show that the early activation of Wnt\r\nsignaling is naturally prevented by Wnt inhibitor factor 1 (Wif1), which is specifically\r\nexpressed in the habenulae until precursors become post-mitotic. Suppression of wif1\r\nphenocopies the effect of early Wnt induction. Furthermore, wif1 expression is\r\npositively regulated by Wnt signaling showing that wif1 is functioning within a\r\nnegative feedback loop. Our data are consistent with a model by which Wif1\r\ndynamically shields early multipotent habenular precursor cells from incoming Wnt\r\nligands secreted by the MDO and possibly other the sources until they become\r\npost-mitotic and differentiate into neurons. wif1 and different Wnt ligands are\r\noverlappingly expressed in a number of developing structures including both the\r\nhabenulae the downstream target the interpenduncular nucleus (IPN). This suggests\r\nthat the Wnt/Wif1 buffering system may serve as a general mechanism for temporally\r\ntuning neurogenesis across the different nuclei of the brain."^^ . "2018" . . . . . . . "Luca"^^ . "Guglielmi"^^ . "Luca Guglielmi"^^ . . . . . . "A Wif1 mediated feedback loop suppresses\r\npremature Wnt signaling in nascent habenular\r\nneurons (PDF)"^^ . . . "PhD thesis Luca Guglielmi.pdf"^^ . . . "A Wif1 mediated feedback loop suppresses\r\npremature Wnt signaling in nascent habenular\r\nneurons (Other)"^^ . . . . . . "indexcodes.txt"^^ . . . "A Wif1 mediated feedback loop suppresses\r\npremature Wnt signaling in nascent habenular\r\nneurons (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "A Wif1 mediated feedback loop suppresses\r\npremature Wnt signaling in nascent habenular\r\nneurons (Other)"^^ . . . . . . "preview.jpg"^^ . . . "A Wif1 mediated feedback loop suppresses\r\npremature Wnt signaling in nascent habenular\r\nneurons (Other)"^^ . . . . . . "medium.jpg"^^ . . . "A Wif1 mediated feedback loop suppresses\r\npremature Wnt signaling in nascent habenular\r\nneurons (Other)"^^ . . . . . . "small.jpg"^^ . . "HTML Summary of #24176 \n\nA Wif1 mediated feedback loop suppresses \npremature Wnt signaling in nascent habenular \nneurons\n\n" . "text/html" . .