scholarly journals An Evolutionarily Conserved Network Mediates Development of the zona limitans intrathalamica, a Sonic Hedgehog-Secreting Caudal Forebrain Signaling Center

2016 ◽  
Vol 4 (4) ◽  
pp. 31 ◽  
Author(s):  
Elena Sena ◽  
Kerstin Feistel ◽  
Béatrice Durand
Keyword(s):  
Sonic Hedgehog ◽  
Zona Limitans Intrathalamica ◽  
Evolutionarily Conserved ◽  
Signaling Center

scholarly journals Cleavage activates Dispatched for Sonic Hedgehog ligand release

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Daniel P Stewart ◽  
Suresh Marada ◽  
William J Bodeen ◽  
Ashley Truong ◽  
Sadie Miki Sakurada ◽  
...  
Keyword(s):  
Sonic Hedgehog ◽  
Membrane Trafficking ◽  
Developmental Disorders ◽  
Transmembrane Protein ◽  
Regulatory Mechanisms ◽  
Extracellular Loop ◽  
Site Mutation ◽  
Evolutionarily Conserved ◽  
Processing Site

Hedgehog ligands activate an evolutionarily conserved signaling pathway that provides instructional cues during tissue morphogenesis, and when corrupted, contributes to developmental disorders and cancer. The transmembrane protein Dispatched is an essential component of the machinery that deploys Hedgehog family ligands from producing cells, and is absolutely required for signaling to long-range targets. Despite this crucial role, regulatory mechanisms controlling Dispatched activity remain largely undefined. Herein, we reveal vertebrate Dispatched is activated by proprotein convertase-mediated cleavage at a conserved processing site in its first extracellular loop. Dispatched processing occurs at the cell surface to instruct its membrane re-localization in polarized epithelial cells. Cleavage site mutation alters Dispatched membrane trafficking and reduces ligand release, leading to compromised pathway activity in vivo. As such, convertase-mediated cleavage is required for Dispatched maturation and functional competency in Hedgehog ligand-producing cells.

scholarly journals FGFs are orchestra conductors of Shh-dependent oligodendroglial fate specification in the ventral spinal cord

2017 ◽  
Author(s):  
Marie-Amélie Farreny ◽  
Eric Agius ◽  
Sophie Bel-Vialar ◽  
Nathalie Escalas ◽  
Nagham Khouri-Farah ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Progenitor Cells ◽  
Sonic Hedgehog ◽  
Fgf Signaling ◽  
Oligodendrocyte Precursor Cell ◽  
Signaling Center ◽  
Oligodendrocyte Precursor ◽  
Prevailing View ◽  
Ventral Spinal Cord

AbstractMost oligodendrocytes of the spinal cord originate from ventral progenitor cells of the pMN domain, characterized by expression of the transcription factor Olig2. A minority of oligodendrocytes is also recognized to emerge from dorsal progenitors during fetal development. The prevailing view is that generation of ventral oligodendrocytes depends on Sonic hedgehog (Shh) while dorsal oligodendrocytes develop under the influence of Fibroblast Growth Factors (FGFs). Using the well-established model of the chicken embryo, we evidence that ventral spinal progenitor cells activate FGF signaling at the onset of oligodendrocyte precursor cell (OPC) generation, as do they dorsal counterpart. Inhibition of FGF receptors at that time appears sufficient to prevent generation of ventral OPCs, highlighting that, in addition to Shh, FGF signaling is required also for generation of ventral OPCs. We further reveal an unsuspected interplay between Shh and FGF signaling by showing that FGFs serve dual essential functions in ventral OPC specification. FGFs are responsible for timely induction of a secondary Shh signaling center, the lateral floor plate, a crucial step to create the burst of Shh required for OPC specification. At the same time, FGFs prevent down-regulation of Olig2 in pMN progenitor cells as these cells receive higher threshold of the Shh signal. Finally, we bring arguments favoring a key role of newly differentiated neurons acting as providers of the FGF signal required to trigger OPC generation in the ventral spinal cord.

Apoptosis and development

2003 ◽  
Vol 39 ◽  
pp. 11-24 ◽  
Author(s):  
Justin V McCarthy
Keyword(s):  
Drosophila Melanogaster ◽  
Mammalian Cells ◽  
Cell Number ◽  
Model Organisms ◽  
Biological Processes ◽  
Nematode Caenorhabditis Elegans ◽  
Apoptotic Pathway ◽  
Genetic Pathways ◽  
Evolutionarily Conserved ◽  
Multicellular Organisms

Apoptosis is an evolutionarily conserved process used by multicellular organisms to developmentally regulate cell number or to eliminate cells that are potentially detrimental to the organism. The large diversity of regulators of apoptosis in mammalian cells and their numerous interactions complicate the analysis of their individual functions, particularly in development. The remarkable conservation of apoptotic mechanisms across species has allowed the genetic pathways of apoptosis determined in lower species, such as the nematode Caenorhabditis elegans and the fruitfly Drosophila melanogaster, to act as models for understanding the biology of apoptosis in mammalian cells. Though many components of the apoptotic pathway are conserved between species, the use of additional model organisms has revealed several important differences and supports the use of model organisms in deciphering complex biological processes such as apoptosis.

672: Regulation of Cavernous Nerve Injury-Induced Apoptosis by Sonic Hedgehog

2007 ◽  
Vol 177 (4S) ◽  
pp. 225-225
Author(s):  
Carol A. Podlasek ◽  
Yi Tang ◽  
Cynthia L. Meraz ◽  
Kevin E. McKenna ◽  
Kevin T. McVary
Keyword(s):  
Nerve Injury ◽  
Sonic Hedgehog ◽  
Cavernous Nerve ◽  
Induced Apoptosis ◽  
Cavernous Nerve Injury
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