Vertebrate, central nervous system patterning

The central nervous system (CNS) of vertebrates is a very complex structure derived from a multistep process involving sequential molecular and morphogenetic events that pattern the epiblast first and the neural plate later. During early gastrulation, the concerted and sequential action of both the anterior visceral endoderm (AVE) and the node and its derivatives (axial mesendoderm, AME, and anterior definitive endoderm, ADE) (Beddington and Robertson, 1999 Bachiller et al., 2000) drives the specification of the anterior neuroectoderm, which subsequently is subdivided in three main territories (forebrain, midbrain, and hindbrain) (Gallera, 1971 Storey et al., 1992 Ruiz i Altaba, 1994 Shimamura and Rubenstein, 1997 Rubenstein and Beachy, 1998). 

Alternative splicing of exons is especially common in the nervous system, generating multiple Isoforms of many proteins required for neuronal development and function in both vertebrates and Invertebrates. The primary transcripts from these genes often show quite complex splicing patterns that can generate several different mRNAs, with different spliced forms expressed in different anatomical locations within the central nervous system. We consider two remarkable examples that Illustrate the critical role of this process in neural function. 

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