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Nature Apr 2020The segmental organization of the vertebral column is established early in embryogenesis, when pairs of somites are rhythmically produced by the presomitic mesoderm...
The segmental organization of the vertebral column is established early in embryogenesis, when pairs of somites are rhythmically produced by the presomitic mesoderm (PSM). The tempo of somite formation is controlled by a molecular oscillator known as the segmentation clock. Although this oscillator has been well-characterized in model organisms, whether a similar oscillator exists in humans remains unknown. Genetic analyses of patients with severe spine segmentation defects have implicated several human orthologues of cyclic genes that are associated with the mouse segmentation clock, suggesting that this oscillator might be conserved in humans. Here we show that human PSM cells derived in vitro-as well as those of the mouse-recapitulate the oscillations of the segmentation clock. Human PSM cells oscillate with a period two times longer than that of mouse cells (5 h versus 2.5 h), but are similarly regulated by FGF, WNT, Notch and YAP signalling. Single-cell RNA sequencing reveals that mouse and human PSM cells in vitro follow a developmental trajectory similar to that of mouse PSM in vivo. Furthermore, we demonstrate that FGF signalling controls the phase and period of oscillations, expanding the role of this pathway beyond its classical interpretation in 'clock and wavefront' models. Our work identifying the human segmentation clock represents an important milestone in understanding human developmental biology.
Topics: Animals; Biological Clocks; Cell Differentiation; Cells, Cultured; Embryonic Development; Female; Fibroblast Growth Factors; Humans; In Vitro Techniques; Male; Mice; Pluripotent Stem Cells; RNA-Seq; Signal Transduction; Single-Cell Analysis; Somites
PubMed: 31915384
DOI: 10.1038/s41586-019-1885-9 -
Journal of the Royal Society, Interface Sep 2019Segment formation in vertebrate embryos is a stunning example of biological self-organization. Here, we present an idealized framework, in which we treat the presomitic...
Segment formation in vertebrate embryos is a stunning example of biological self-organization. Here, we present an idealized framework, in which we treat the presomitic mesoderm (PSM) as a one-dimensional line of oscillators. We use the framework to derive constraints that connect the size of somites, and the timing of their formation, to the growth of the PSM and the gradient of the somitogenesis clock period across the PSM. Our analysis recapitulates the observations made recently in cultures of mouse PSM cells, and makes predictions for how perturbations, such as increased Wnt levels, would alter somite widths. Finally, our analysis makes testable predictions for the shape of the phase profile and somite widths at different stages of PSM growth. In particular, we show that the phase profile is robustly concave when the PSM length is steady and slightly convex in an important special case when it is decreasing exponentially. In both cases, the phase profile scales with the PSM length; in the latter case, it scales dynamically. This has important consequences for the velocity of the waves that traverse the PSM and trigger somite formation, as well as the effect of errors in phase measurement on somite widths.
Topics: Animals; Body Patterning; Embryo, Mammalian; Embryonic Development; Gene Expression Regulation, Developmental; Mice; Somites; Wnt Signaling Pathway
PubMed: 31530134
DOI: 10.1098/rsif.2019.0451 -
Genes Mar 2020In this review, we highlight information on microRNA (miRNA) identification and functional characterization in the beef for muscle and carcass composition traits, with... (Review)
Review
In this review, we highlight information on microRNA (miRNA) identification and functional characterization in the beef for muscle and carcass composition traits, with an emphasis on Qinchuan beef cattle, and discuss the current challenges and future directions for the use of miRNA as a biomarker in cattle for breeding programs to improve meat quality and carcass traits. MicroRNAs are endogenous and non-coding RNA that have the function of making post-transcriptional modifications during the process of preadipocyte differentiation in mammals. Many studies claim that diverse miRNAs have an impact on adipogenesis. Furthermore, their target genes are associated with every phase of adipocyte differentiation. It has been confirmed that, during adipogenesis, several miRNAs are differentially expressed, including miR-204, miR-224, and miR-33. The development of mammalian skeletal muscle is sequentially controlled by somite commitment into progenitor cells, followed by their fusion and migration, the proliferation of myoblasts, and final modification into fast- and slow-twitch muscle fibers. It has been reported that miRNA in the bovine MEG3-DIO3 locus has a regulatory function for myoblast differentiation. Likewise, miR-224 has been associated with controlling the differentiation of bovine adipocytes by targeting lipoprotein lipase. Through the posttranscriptional downregulation of KLF6, miR-148a-3p disrupts the proliferation of bovine myoblasts and stimulates apoptosis while the miR-23a~27a~24-2 cluster represses adipogenesis. Additional to influences on muscle and fat, bta-mir-182, bta-mir-183, and bta-mir-338 represent regulators of proteolysis in muscle, which influences meat tenderness.
Topics: Animals; Cattle; MicroRNAs; Muscle, Skeletal; Quantitative Trait, Heritable; Red Meat
PubMed: 32168744
DOI: 10.3390/genes11030295 -
Scientific Reports Jul 2023The establishment of left-right patterning in mice occurs at a transient structure called the embryonic node or left-right organizer (LRO). Previous analysis of the LRO...
The establishment of left-right patterning in mice occurs at a transient structure called the embryonic node or left-right organizer (LRO). Previous analysis of the LRO has proven challenging due to the small cell number and transient nature of this structure. Here, we seek to overcome these difficulties to define the transcriptome of the LRO. Specifically, we used single cell RNA sequencing of 0-1 somite embryos to identify LRO enriched genes which were compared to bulk RNA sequencing of LRO cells isolated by fluorescent activated cell sorting. Gene ontology analysis indicated an enrichment of genes associated with cilia and laterality terms. Furthermore, comparison to previously identified LRO genes identified 127 novel LRO genes, including Ttll3, Syne1 and Sparcl1, for which the expression patterns were validated using whole mount in situ hybridization. This list of novel LRO genes will be a useful resource for further studies on LRO morphogenesis, the establishment of laterality and the genetic causes of heterotaxy.
Topics: Animals; Mice; Transcriptome; Cell Count; Cell Separation; Cilia; RNA; Calcium-Binding Proteins; Extracellular Matrix Proteins
PubMed: 37393374
DOI: 10.1038/s41598-023-36862-2 -
Frontiers in Cell and Developmental... 2022During vertebrate development, symmetry breaking occurs in the left-right organizer (LRO). The transfer of asymmetric molecular information to the lateral plate mesoderm...
During vertebrate development, symmetry breaking occurs in the left-right organizer (LRO). The transfer of asymmetric molecular information to the lateral plate mesoderm is essential for the precise patterning of asymmetric internal organs, such as the heart. However, at the same developmental time, it is crucial to maintain symmetry at the somite level for correct musculature and vertebrae specification. We demonstrate how left-right signals affect the behavior of zebrafish somite cell precursors by using live imaging and fate mapping studies in dand5 homozygous mutants compared to wildtype embryos. We describe a population of cells in the vicinity of the LRO, named Non-KV Sox17:GFP+ Tailbud Cells (NKSTCs), which migrate anteriorly and contribute to future somites. We show that NKSTCs originate in a cluster of cells aligned with the midline, posterior to the LRO, and leave that cluster in a left-right alternating manner, primarily from the left side. Fate mapping revealed that more NKSTCs integrated somites on the left side of the embryo. We then abolished the asymmetric cues from the LRO using dand5-/- mutant embryos and verified that NKSTCs no longer displayed asymmetric patterns. Cell exit from the posterior cluster became bilaterally synchronous in dand5-/- mutants. Our study revealed a new link between somite specification and Dand5 function. The gene dand5 is well known as the first asymmetric gene involved in vertebrate LR development. This study revealed a new link for Dand5 as a player in cell exit from the maturation zone into the presomitic mesoderm, affecting the expression patterns of myogenic factors and tail size.
PubMed: 36699016
DOI: 10.3389/fcell.2022.989615 -
Frontiers in Cell and Developmental... 2022Vertebrate embryo somitogenesis is the earliest morphological manifestation of the characteristic patterned structure of the adult axial skeleton. Pairs of somites... (Review)
Review
Vertebrate embryo somitogenesis is the earliest morphological manifestation of the characteristic patterned structure of the adult axial skeleton. Pairs of somites flanking the neural tube are formed periodically during early development, and the molecular mechanisms in temporal control of this early patterning event have been thoroughly studied. The discovery of a molecular Embryo Clock (EC) underlying the periodicity of somite formation shed light on the importance of gene expression dynamics for pattern formation. The EC is now known to be present in all vertebrate organisms studied and this mechanism was also described in limb development and stem cell differentiation. An outstanding question, however, remains unanswered: what sets the different EC paces observed in different organisms and tissues? This review aims to summarize the available knowledge regarding the pace of the EC, its regulation and experimental manipulation and to expose new questions that might help shed light on what is still to unveil.
PubMed: 36036002
DOI: 10.3389/fcell.2022.944016 -
International Journal of Molecular... Sep 2023represents a type of single-transmembrane adaptor protein containing an N-terminal cysteine-rich domain and a proline-rich C-terminal region. Nine subfamily genes have...
represents a type of single-transmembrane adaptor protein containing an N-terminal cysteine-rich domain and a proline-rich C-terminal region. Nine subfamily genes have been proposed in most vertebrates; however, some might be species-specific. The number of genes present in zebrafish remains unclear. This study aimed to investigate the evolutionary relationships among family genes in zebrafish (TU strain) using phylogenetic and syntenic analyses. The function of was preliminarily examined via CRISPR/Cas13d-mediated knockdown. Following identification in zebrafish, 10 family genes, namely , , , , , , , , , and , were classified into three main clades and six subclades. Their encoding proteins contained a cysteine-rich N-terminal domain and a proline-rich C-terminal region containing different motifs. A specific syntenic block containing and was observed to be conserved across all species. Furthermore, all these genes were expressed during embryogenesis. was expressed in the presomitic mesoderm, somites, and so on. was identified as a regulator of the expression of the somite formation marker . Overall, our study provides new insights into the evolution of family genes and the control of over the convergent extension cells of somitic precursors in zebrafish.
Topics: Animals; Zebrafish; Zebrafish Proteins; Phylogeny; Cysteine; Membrane Proteins; Proline; Gene Expression Regulation, Developmental
PubMed: 37762365
DOI: 10.3390/ijms241814062 -
Experimental & Molecular Medicine Aug 2020Pluripotent stem cells (PSCs) are attractive regenerative therapy tools for skeletal tissues. However, a deep understanding of skeletal development is required in order... (Review)
Review
Pluripotent stem cells (PSCs) are attractive regenerative therapy tools for skeletal tissues. However, a deep understanding of skeletal development is required in order to model this development with PSCs, and for the application of PSCs in clinical settings. Skeletal tissues originate from three types of cell populations: the paraxial mesoderm, lateral plate mesoderm, and neural crest. The paraxial mesoderm gives rise to the sclerotome mainly through somitogenesis. In this process, key developmental processes, including initiation of the segmentation clock, formation of the determination front, and the mesenchymal-epithelial transition, are sequentially coordinated. The sclerotome further forms vertebral columns and contributes to various other tissues, such as tendons, vessels (including the dorsal aorta), and even meninges. To understand the molecular mechanisms underlying these developmental processes, extensive studies have been conducted. These studies have demonstrated that a gradient of activities involving multiple signaling pathways specify the embryonic axis and induce cell-type-specific master transcription factors in a spatiotemporal manner. Moreover, applying the knowledge of mesoderm development, researchers have attempted to recapitulate the in vivo development processes in in vitro settings, using mouse and human PSCs. In this review, we summarize the state-of-the-art understanding of mesoderm development and in vitro modeling of mesoderm development using PSCs. We also discuss future perspectives on the use of PSCs to generate skeletal tissues for basic research and clinical applications.
Topics: Animals; Bone Development; Bone and Bones; Humans; Mesoderm; Pluripotent Stem Cells; Somites; Wound Healing
PubMed: 32788657
DOI: 10.1038/s12276-020-0482-1 -
Development, Growth & Differentiation Feb 2021Segmental organization of the vertebrate body plan is established by the segmentation clock, a molecular oscillator that controls the periodicity of somite formation.... (Review)
Review
Segmental organization of the vertebrate body plan is established by the segmentation clock, a molecular oscillator that controls the periodicity of somite formation. Given the dynamic nature of the segmentation clock, in vivo studies in vertebrate embryos pose technical challenges. As an alternative, simpler models of the segmentation clock based on primary explants and pluripotent stem cells have recently been developed. These ex vivo and in vitro systems enable more quantitative analysis of oscillatory properties and expand the experimental repertoire applicable to the segmentation clock. Crucially, by eliminating the need for model organisms, in vitro models allow us to study the segmentation clock in new species, including our own. The human oscillator was recently recapitulated using induced pluripotent stem cells, providing a window into human development. Certainly, a combination of in vivo and in vitro work holds the most promising potential to unravel the mechanisms behind vertebrate segmentation.
Topics: Biological Clocks; Cell Differentiation; Humans; Pluripotent Stem Cells
PubMed: 33460448
DOI: 10.1111/dgd.12710 -
Developmental Biology Apr 2020Spatial patterning during embryonic development emerges from the differentiation of progenitor cells that share the same genetic program. One of the main challenges in... (Review)
Review
Spatial patterning during embryonic development emerges from the differentiation of progenitor cells that share the same genetic program. One of the main challenges in systems biology is to understand the relationship between gene network and patterning, especially how the cells communicate to coordinate their differentiation. This review aims to describe the principles of pattern formation from local cell-cell interactions mediated by the Notch signalling pathway. Notch mediates signalling via direct cell-cell contact and regulates cell fate decisions in many tissues during embryonic development. Here, I will describe the patterning mechanisms via different Notch ligands and the critical role of Notch oscillations during the segmentation of the vertebrate body, brain development, and blood vessel formation.
Topics: Animals; Body Patterning; Cell Communication; Embryonic Development; Gene Expression Regulation, Developmental; Intracellular Signaling Peptides and Proteins; Membrane Proteins; Mice; Neovascularization, Physiologic; Neurogenesis; Receptors, Notch; Serrate-Jagged Proteins; Signal Transduction; Somites; Transcription Factor HES-1; Zebrafish
PubMed: 31866513
DOI: 10.1016/j.ydbio.2019.12.008