P Bovolenta

..Furthermore, retroviral mediated expression of a dominant-negative form of GSK3beta induced a retina phenotype similar to that observed after Sfrp1 overexpression, suggesting a possible involvement of this kinase in SFRP1 function...

..Here we review some of the debated aspects of SFRP-Wnt interactions and discuss the new and emerging roles of SFRPs...

..Due to its structural relationship with Fz, it is believed that SfrpCRD interferes with Wnt signalling by binding and sequestering the ligand. In contrast, the functional relevance of the SfrpNTR has been barely addressed...

..To address this issue, we have focused on Six3, an important regulator of vertebrate forebrain development...

..The data that support this conclusion will be summarized and how morphogens may signal at the growth cone will be discussed...

..In the developing neural retina, cSix3 is expressed in the entire undifferentiated neuroepithelium but is rapidly downregulated, first in the postmitotic photoreceptors and later in the majority of retinal ganglion cells...

..Special emphasis will be placed on those studies that have shown that proteoglycans of certain subtypes inhibit neurite extension either during the development and/or the regeneration of the vertebrate Central Nervous System...

..3-q23 with bilateral anophthalmia and pituitary anomalies. Genomic analyses of one of these cases demonstrated SIX6 hemizygosity, strongly suggesting that SIX6 haploinsufficiency is responsible for these developmental disorders...

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..These results provide evidence that BMP4 contributes to eye development by promoting cell proliferation and programmed cell death...

..Our data indicate that early cell death is an important process in the neurogenesis of retinal ganglion cells and is regulated by locally produced BDNF...

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..Based on these findings, we propose that Shh expression at the chiasm border defines a constrained pathway within the ventral midline which serves to guide the progression of RGC axons...

..Here, we have summarised the evidence for this novel idea with a particular emphasis on those related to Shh and Wnt signalling-the object of some works in our laboratory...

..Collectively, these data suggest that both transcription factors operate at the same hierarchical level to establish the identity of the RPE...

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..Interestingly, the map position of human SIX3 overlaps the locations of two dominant disorders with ocular phenotypes that have been assigned to this chromosomal region, holoprosencephaly type 2 and Malattia Leventinese...

..Collectively, these data indicate that BMP7 is required for retinal fissure formation and that its activity is needed, before SHH signalling, for the generation of PAX2-positive cells at the optic disc...

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..Therefore, a more precise understanding of the molecular mechanisms that underlie the different responses to SHH signalling is the next step in the study of this molecule and its role in the regulation of neural development...

..These distinct patterns support the idea that Six 3 and Six 6 are differentially required during forebrain development...

..These data indicate that both Tle1 and Aes participate in the molecular network that control eye development and are consistent with the view that both Six3 and Six6 act in combination with either Tle1 and/or Aes...

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..Our data demonstrate that the Meox genes are required for Bapx1 expression in the sclerotome and suggest that the mechanism by which the Meox proteins exert this function is through direct activation of the Bapx1 gene...

..Here, we summarise the evidence that relates Sfrps with these diseases and discuss how the proposed multiple Sfrp interactions with Wnt related and unrelated pathways may explain their implication in such diverse pathologies...

..The results point to an important role of olSfrp5 in visual system formation and indicate that olSfrp1 and olSfrp5, despite their overlapping expression, have only partially redundant function during eye development...

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..Together, these results indicate that Six6 and NeuroD control the expression of each other and their functions coordinate amacrine cell generation and photoreceptor terminal differentiation...

..In addition, olSfrp1 may contribute to the control of mesodermal convergence extension movements that take place during gastrulation...

..Because the genetic causes of many retinal dystrophies still need to be determined, we have asked whether mutations in the SFRP genes might be associated with retinal dystrophies...

..Furthermore, using this information and the data available on the specification of the pigmented cells of primitive chordates, we have ventured some hypotheses on the origin of RPE cells during evolution...

..In addition, later on in development, Fgf controls the onset of retinal neurogenesis and Shh and GDF11 control its feedback regulation...

..These demonstrate critical roles of Cux in dendritogenesis and highlight subclass-specific mechanisms of synapse regulation that contribute to the establishment of cognitive circuits...

..Altogether these data indicate that Shh contributes to OPC proliferation and distribution along the ON, in addition to their specification...

..The concerted activity of Fgf8 and Fgf3 is both necessary and sufficient to coordinate retinal differentiation independent of the connecting optic stalk...

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..The presence of aralar1 could reflect a tonic activity of these neurons, which is met by the combination of high malate-aspartate NADH shuttle and respiratory chain activities...

..This explains why citrin deficiency in humans (type II citrullinemia) only affects the liver and suggests that aralar1 may compensate for the lack of citrin in other tissues...