emx3 is first expressed in prospective telencephalic cells at the anterior border of the zebrafish neural plate. Knockdown of Emx3 function by morpholino reduces the expression of markers specific to dorsal telencephalon, and impairs axon tract formation. Rescue of both early and late markers requires low-level expression of emx3 at the one- or two-somite stage. Higher emx3 expression levels cause dorsal telencephalic markers to expand ventrally, which points to a possible role of emx3 in specifying dorsal telencephalon and a potential new function for Wnt/beta-catenin pathway activation. In contrast to mice, where Emx2 plays a major role in dorsal telencephalic development, knockdown of zebrafish Emx2 apparently does not affect telencephalic development. Similarly, Emx1 knockdown has little effect. Previously, emx3 was thought to be fish-specific. However, we found all three emx orthologs in Xenopus tropicalis and opossum (Monodelphis domestica) genomes, indicating that emx3 was present in an ancestral tetrapod genome.
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http://dx.doi.org/10.1002/dvdy.22031 | DOI Listing |
Stem Cell Reports
December 2024
Laboratorio di Biologia, Scuola Normale Superiore, 56126 Pisa, Italy; Istituto di Biofisica, Consiglio Nazionale delle Ricerche, 56124 Pisa, Italy. Electronic address:
The mechanisms that determine distinct embryonic pallial identities remain elusive. The central role of Wnt signaling in directing dorsal telencephalic progenitors to the isocortex or hippocampus has been elucidated. Here, we show that timely inhibition of MAPK/ERK and BMP signaling in neuralized mouse embryonic stem cells (ESCs) specifies a cell identity characteristic of the allocortex.
View Article and Find Full Text PDFEpilepsia
December 2024
Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, Ohio, USA.
Objective: Brain somatic variants in SLC35A2 were recently identified as a genetic marker for mild malformations of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE). The role of SLC35A2 in cortical development and the contributions of abnormal neurons and oligodendrocytes to seizure activity in MOGHE remain largely unexplored.
Methods: Here, we generated a novel Slc35a2 floxed allele, which we used to develop two Slc35a2 conditional knockout mouse lines targeting (1) the Emx1 dorsal telencephalic lineage (excitatory neurons and glia) and (2) the Olig2 lineage (oligodendrocytes).
Brain Behav Evol
October 2024
Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA.
Background: Most studies comparing forebrain organization between reptiles and mammals have focused on similarities. Equally important are the differences between their brains. While differences have been addressed infrequently, this approach can highlight the evolution of brains in relation to their respective environments.
View Article and Find Full Text PDFEMBO J
November 2024
Department of Anesthesia, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, and Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
J Neurosci
September 2024
Department of Biochemistry and Molecular Biology, Schools of Biology and Chemistry, Instituto Universitario de Investigación Neuroquímica (IUIN), Complutense University, Madrid ES-28040, Spain
Growth-associated protein of 43 kDa (GAP43) is a key cytoskeleton-associated component of the presynaptic terminal that facilitates neuroplasticity. Downregulation of GAP43 expression has been associated to various psychiatric conditions in humans and evokes hippocampus-dependent memory impairments in mice. Despite the extensive studies conducted on hippocampal GAP43 in past decades, however, very little is known about its roles in modulating the excitatory versus inhibitory balance in other brain regions.
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