[The lateral somitic frontier: The source of multipotent somitic cells in Xenopus].

The somites are embryonic structures that give rise to the axial musculoskeletal system. In amniotes vertebrates, somites are composed of multipotent somitic cells that quickly compartmentalize into a dorsal dermomyotome and a ventral sclerotome. In the somites, the dermomyotome gives rise to skeletal muscle cells (the myotome) and the dorsal dermis (the dermatome), while the sclerotome gives rise to vertebrae, ribs, and dorsal tendons (the syndetome).

The collagen ColQ binds to LRP4 and regulates the activation of the Muscle-Specific Kinase-LRP4 receptor complex by agrin at the neuromuscular junction.

Collagen Q (ColQ) is a nonfibrillar collagen that plays a crucial role at the vertebrate neuromuscular junction (NMJ) by anchoring acetylcholinesterase to the synapse. ColQ also functions in signaling, as it regulates acetylcholine receptor clustering and synaptic gene expression, in a manner dependent on muscle-specific kinase (MuSK), a key protein in NMJ formation and maintenance. MuSK forms a complex with low-density lipoprotein receptor-related protein 4 (LRP4), its coreceptor for the proteoglycan agrin at the NMJ.

Activating ATF6 in spinal muscular atrophy promotes SMN expression and motor neuron survival through the IRE1α-XBP1 pathway.

Aim: Spinal muscular atrophy (SMA) is a neuromuscular disease caused by survival of motor neuron (SMN) deficiency that induces motor neuron (MN) degeneration and severe muscular atrophy. Gene therapies that increase SMN have proven their efficacy but not for all patients. Here, we explored the unfolded protein response (UPR) status in SMA pathology and explored whether UPR modulation could be beneficial for SMA patients.

Evolution of Somite Compartmentalization: A View From .

Somites are transitory metameric structures at the basis of the axial organization of vertebrate musculoskeletal system. During evolution, somites appear in the chordate phylum and compartmentalize mainly into the dermomyotome, the myotome, and the sclerotome in vertebrates. In this review, we summarized the existing literature about somite compartmentalization in and compared it with other anamniote and amniote vertebrates.

Lineage tracing of sclerotome cells in amphibian reveals that multipotent somitic cells originate from lateral somitic frontier.

The two somite compartments, dorso-lateral dermomyotome and medio-ventral sclerotome are major vertebrate novelties, but little is known about their evolutionary origin. We determined that sclerotome cells in Xenopus come from lateral somitic frontier (LSF) by lineage tracing, ablation experiments and histological analysis. We identified Twist1 as marker of migrating sclerotome progenitors in two amphibians, Xenopus and axolotl.