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Journal of Anatomy Apr 2018A prominent anatomical feature of the peripheral nervous system is the segmentation of mixed (motor, sensory and autonomic) spinal nerves alongside the spinal cord.... (Review)
Review
A prominent anatomical feature of the peripheral nervous system is the segmentation of mixed (motor, sensory and autonomic) spinal nerves alongside the spinal cord. During early development their axon growth cones avoid the developing vertebral elements by traversing the anterior/cranial half of each somite-derived sclerotome, so ensuring the separation of spinal nerves from vertebral bones as axons extend towards their peripheral targets. A glycoprotein expressed on the surface of posterior half-sclerotome cells confines growth cones to the anterior half-sclerotomes by contact repulsion. A closely similar glycoprotein is expressed in avian and mammalian grey matter, where we hypothesize it may have evolved to regulate neural plasticity in birds and mammals.
Topics: Animals; Body Patterning; Chick Embryo; Growth Cones; Humans; Mice; Nerve Growth Factor; Somites; Spinal Cord; Spinal Nerves; Spine
PubMed: 29063597
DOI: 10.1111/joa.12714 -
ELife May 2018The patterning of the spine of a zebrafish is controlled by the notochord, a rod-like structure that supports and instructs the developing embryo.
The patterning of the spine of a zebrafish is controlled by the notochord, a rod-like structure that supports and instructs the developing embryo.
Topics: Animals; Body Patterning; Bone and Bones; Notochord; Spine; Zebrafish
PubMed: 29767626
DOI: 10.7554/eLife.37288 -
Acta Histochemica 2015Myogenesis is controlled by an elaborate system of extrinsic and intrinsic regulatory mechanisms in all development stages. The aim of this review is to provide an... (Review)
Review
Myogenesis is controlled by an elaborate system of extrinsic and intrinsic regulatory mechanisms in all development stages. The aim of this review is to provide an overview of the different stages of myogenesis and muscle differentiation in mammals, starting from somitogenesis and analysis of the different portions that constitute the mature somite. Particular attention was paid to regulatory genes, in addition to mesodermal stem cells, which represent the earliest elements of myogenesis. Finally, the crucial role of growth factors, molecules of vital importance in contractile regulation, hormones and their function in skeletal muscle differentiation, growth and metabolism, and the role played by central nervous system, are discussed.
Topics: Animals; Cell Differentiation; Gene Expression Regulation, Developmental; Humans; Intercellular Signaling Peptides and Proteins; Muscle Development; Muscle, Skeletal; Somites; Stem Cells
PubMed: 25850375
DOI: 10.1016/j.acthis.2015.02.011 -
Seminars in Cell & Developmental Biology Jan 2016The segmental organization of the vertebrate body is most obviously visible in the vertebral column, which consists of a series of vertebral bones and interconnecting... (Review)
Review
The segmental organization of the vertebrate body is most obviously visible in the vertebral column, which consists of a series of vertebral bones and interconnecting joints and ligaments. During embryogenesis, the vertebral column derives from the somites, which are the primary segments of the embryonic paraxial mesoderm. Anatomical, cellular and molecular aspects of vertebral column development have been of interest to developmental biologists for more than 150 years. This review briefly summarizes the present knowledge on early steps of vertebral column development in amniotes, starting from sclerotome formation and leading to the establishment of the anatomical bauplan of the spine composed of vertebral bodies, vertebral arches, intervertebral discs and ribs, and their specific axial identities along the body axis.
Topics: Animals; Gene Expression; Gene Expression Regulation, Developmental; Humans; Intervertebral Disc; Ligaments; Spine; Tendons; Zygapophyseal Joint
PubMed: 26564689
DOI: 10.1016/j.semcdb.2015.11.003 -
Developmental Cell Oct 2023The mammalian body plan is shaped by rhythmic segmentation of mesoderm into somites, which are transient embryonic structures that form down each side of the neural...
The mammalian body plan is shaped by rhythmic segmentation of mesoderm into somites, which are transient embryonic structures that form down each side of the neural tube. We have analyzed the genome-wide transcriptional and chromatin dynamics occurring within nascent somites, from early inception of somitogenesis to the latest stages of body plan establishment. We created matched gene expression and open chromatin maps for the three leading pairs of somites at six time points during mouse embryonic development. We show that the rate of somite differentiation accelerates as development progresses. We identified a conserved maturation program followed by all somites, but somites from more developed embryos concomitantly switch on differentiation programs from derivative cell lineages soon after segmentation. Integrated analysis of the somitic transcriptional and chromatin activities identified opposing regulatory modules controlling the onset of differentiation. Our results provide a powerful, high-resolution view of the molecular genetics underlying somitic development in mammals.
Topics: Pregnancy; Female; Mice; Animals; Somites; Embryonic Development; Mesoderm; Cell Differentiation; Chromatin; Mammals
PubMed: 37499658
DOI: 10.1016/j.devcel.2023.07.003 -
Seminars in Cell & Developmental Biology Jun 2015During development, vertebrate embryos produce serially repeated elements, the somites, on each side of the midline. These generate the vertebral column, skeletal... (Review)
Review
During development, vertebrate embryos produce serially repeated elements, the somites, on each side of the midline. These generate the vertebral column, skeletal musculature and dermis. They form sequentially, one pair at a time, from mesenchymal tissue near the tail. Somite development is a complex process. The embryo must control the number, size, and timing of somite formation, their subdivision into functional regions along three axes, regional identity such that somites develop in a region-specific way, and interactions with neighbouring tissues that coordinate them with nearby structures. Here we discuss many timing-related mechanisms that contribute to set up the spatial pattern.
Topics: Animals; Body Patterning; Gene Expression Regulation; Homeodomain Proteins; Signal Transduction; Somites; Vertebrates
PubMed: 26116228
DOI: 10.1016/j.semcdb.2015.06.002 -
Current Topics in Developmental Biology 2024The Segmentation Clock is a tissue-level patterning system that enables the segmentation of the vertebral column precursors into transient multicellular blocks called... (Review)
Review
The Segmentation Clock is a tissue-level patterning system that enables the segmentation of the vertebral column precursors into transient multicellular blocks called somites. This patterning system comprises a set of elements that are essential for correct segmentation. Under the so-called "Clock and Wavefront" model, the system consists of two elements, a genetic oscillator that manifests itself as traveling waves of gene expression, and a regressing wavefront that transforms the temporally periodic signal encoded in the oscillations into a permanent spatially periodic pattern of somite boundaries. Over the last twenty years, every new discovery about the Segmentation Clock has been tightly linked to the nomenclature of the "Clock and Wavefront" model. This constrained allocation of discoveries into these two elements has generated long-standing debates in the field as what defines molecularly the wavefront and how and where the interaction between the two elements establishes the future somite boundaries. In this review, we propose an expansion of the "Clock and Wavefront" model into three elements, "Clock", "Wavefront" and signaling gradients. We first provide a detailed description of the components and regulatory mechanisms of each element, and we then examine how the spatiotemporal integration of the three elements leads to the establishment of the presumptive somite boundaries. To be as exhaustive as possible, we focus on the Segmentation Clock in zebrafish. Furthermore, we show how this three-element expansion of the model provides a better understanding of the somite formation process and we emphasize where our current understanding of this patterning system remains obscure.
Topics: Animals; Body Patterning; Gene Expression Regulation, Developmental; Somites; Mesoderm; Zebrafish; Signal Transduction; Biological Clocks
PubMed: 38729682
DOI: 10.1016/bs.ctdb.2023.11.001 -
PLoS Genetics Jun 2023Four SIX homeoproteins display a combinatorial expression throughout embryonic developmental myogenesis and they modulate the expression of the myogenic regulatory...
Four SIX homeoproteins display a combinatorial expression throughout embryonic developmental myogenesis and they modulate the expression of the myogenic regulatory factors. Here, we provide a deep characterization of their role in distinct mouse developmental territories. We showed, at the hypaxial level, that the Six1:Six4 double knockout (dKO) somitic precursor cells adopt a smooth muscle fate and lose their myogenic identity. At the epaxial level, we demonstrated by the analysis of Six quadruple KO (qKO) embryos, that SIX are required for fetal myogenesis, and for the maintenance of PAX7+ progenitor cells, which differentiated prematurely and are lost by the end of fetal development in qKO embryos. Finally, we showed that Six1 and Six2 are required to establish craniofacial myogenesis by controlling the expression of Myf5. We have thus described an unknown role for SIX proteins in the control of myogenesis at different embryonic levels and refined their involvement in the genetic cascades operating at the head level and in the genesis of myogenic stem cells.
Topics: Mice; Animals; Homeodomain Proteins; Cell Differentiation; Somites; Muscle Development; Gene Expression Regulation, Developmental; Muscle, Skeletal
PubMed: 37267426
DOI: 10.1371/journal.pgen.1010781 -
Developmental Biology May 2022
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Advances in Experimental Medicine and... 2018Zic family proteins have been investigated in various biomedical studies. Here we summarize the contact points between Zic proteins and recent medical research. The... (Review)
Review
Zic family proteins have been investigated in various biomedical studies. Here we summarize the contact points between Zic proteins and recent medical research. The topics cover a wide range, reflecting the pleiotropic roles of these proteins in early embryogenesis and organogenesis. Zic1, Zic2, and Zic3 proteins play important roles in the development of axial and limb bones, and of muscles, among the derivatives of the notochord and somites. Zic1 is involved in bone's response to mechanical stress, and it also serves as a marker specific for brown adipocytes. Zic1, Zic2, Zic3, and Zic5 proteins are required for the development of neural crest derivatives, including the meningeal membrane and facial bones, and deficiency of these proteins causes cortical lamination defects resembling those in type II lissencephaly. In vascular systems, Zic3 is associated not only with normal cardiovascular development, failure of which causes congenital heart anomalies, but also controls maturation of the blood-brain barrier. Zic1 is also expressed in the brain pericytes possessing stem cell properties that control the blood-brain barrier activity and capillary hemodynamic responses. The possible involvement of Zic proteins in neuropsychiatric disorders has been indicated by the analyses of mutant mice behaviors. Zic1 and Zic3 mutant mice show hypotonia and decreased locomotor activities. Zic2 hypomorphic mutant mice exhibit schizophrenia-related behavioral abnormalities such as cognitive dysfunction and impaired sensorimotor gating and social behaviors, and ZIC2 mutations found in schizophrenia patients included a severely functionally defective one. Based on these facts, the application of Zic protein activities in translational medicine might be considered.
Topics: Animals; Biomedical Research; Cognitive Dysfunction; Heart Defects, Congenital; Humans; Mice; Multigene Family; Mutation; Schizophrenia; Transcription Factors; Zinc Fingers
PubMed: 29442325
DOI: 10.1007/978-981-10-7311-3_12