Principles of Early Vertebrate Forebrain Formation
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The formation of the vertebrate central nervous system begins at the onset of gastrulation with the specification of the neuroectoderm or neural plate. This flat sheet of neuroepithelial cells is further patterned along its main axes as it undergoes a complex morphogenetic reorganisation to give rise to the priomordia of the brain and the spinal cord. In this chapter, we provide a basic overview of the regulatory networks that couple patterning and morphogenesis of the forebrain primordium, which arises from the most anterior part of the neural plate and comprises the telencephalic, retinal, hypothalamic and diencephalic fields. We will describe that, as it occurs in other regions of the developing embryo, morphogenesis and specification of the forebrain primordium is coordinated by a constantly evolving combination of a reduced number of signalling pathways and transcription factors, which together form highly interconnected gene regulatory networks. We will also discuss the still fragmentary information showing that the expression levels of the components of these networks is fine-tuned by different species of non-translated RNAs, which further contribute to originate forebrain complexity from a limited number of key genes.
KeywordsTranscription factors Transcriptional networks Morphogens Cell signalling Forebrain Eye Retina Telencephalon Cell cohesion Patterning microRNA
Work in our lab is supported by grants from the Spanish Government MINECO (BFU2014-55918-P to F.C.; BFU-2013-43213-P and BFU2014-55738-REDT to P.B.), the European Commission (CIG321788 to F.C. and P.B.); the Comunidad Autonoma de Madrid (CAM; S2010/BMD-2315 to P.B.); the CIBERER, ISCIII to P.B. and by an Institutional Grant from the Fundación Ramon Areces.
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