The International journal of developmental biology最新文献

Understanding the structure and function of cells is central to cell biology and physiology. The ability to control cell function may benefit biomedicine, such as cell-replacement therapy or regeneration. If structure defines function and cells are composed of water, lipids, small metabolites, nucleic acids, and proteins, of which the latter are largely encoded by the DNA present in the same cell, then one may assume that the cell types and variation in cellular phenotypes are shaped by differential gene expression. Cells of the same cell type maintain a similar composition. In this review, I will discuss the epigenetic and transcription regulation mechanisms guiding cell fate- specific gene expression in developing neural cells. Differentiation involves processes of cell-fate selection, commitment and maturation, which are not necessarily coupled.

The presence of horns in domestic ruminants, such as cattle, sheep and goats, has financial and welfare implications. The genetic interactions that lead to horn development are not known. Hornless, or polled, cattle occur naturally. The known causative DNA variants (Celtic, Friesian, Mongolian and Guarani) are in intergenic regions on bovine chromosome 1, but their functions are not known. It is thought that horns may be derived from cranial neural crest stem cells and the POLLED variants disrupt the migration or proliferation of these cells. Relaxin family peptide receptor 2 (RXFP2) is more highly expressed in developing horns in cattle compared to nearby skin and has been shown to play a role in horn development in sheep. However, the role of RXFP2 in horn formation is not understood. Histological analyses of cranial tissues from homozygous horned and polled cattle fetuses at day 58 of development was carried out to determine the differences in the structure of the horn bud region. Condensed cells were only observed in the horn bud mesenchyme of horned fetuses and could be the progenitor horn cells. The distribution of neural crest markers (SOX10 and NGFR) and RXFP2 between horned and polled tissues by immunohistochemistry was also analysed. However, SOX10 and NGFR were not detected in the condensed cells, and therefore, these cells are either not derived from the neural crest, or have differentiated and no longer express neural crest markers. SOX10 and NGFR were detected in the peripheral nerves, while RXFP2 was detected in peripheral nerves and in the horn bud epidermis. Previous research has shown that RXFP2 variants are associated with horn phenotypes in cattle an sheep. Therefore, the RXFP2 variants may affect the development of the epidermis or peripheral nerves in the horn bud.

Lymphatic vessels within different organs have diverse developmental origins, depend on different growth factor signaling pathways for their development and maintenance, and display notable tissue-specific adaptations that contribute to their roles in normal physiology and in various diseases. Functional studies on the lymphatic vasculature rely extensively on the use of mouse models that allow selective gene targeting of lymphatic endothelial cells (LECs). Here, we discuss LEC diversity and provide an overview of some of the commonly used LEC-specific inducible Cre lines and induction protocols, outlining essential experimental parameters and their implications. We describe optimized treatment regimens for embryonic, postnatal and adult LECs, efficiently targeting organs that are commonly studied in lymphatic vascular research, such as the mesentery and skin. We further highlight the anticipated outcomes and limitations associated with each induction scheme and mouse line. The proposed protocols serve as recommendations for laboratories initiating studies involving targeting of the lymphatic vasculature, and aim to promote uniformity in lineage tracing and functional studies within the lymphatic vascular field.

The digestive tract is a series of organs with specific functions and specialized anatomy. Each organ is organized similarly with concentric layers of epithelial, connective, smooth muscle, and neural tissues. Interstitial cells of Cajal (ICC) are distributed in smooth muscle layers and contribute to the organization of repetitive and rhythmic smooth muscle contractions. Understanding ICC development is critical to understanding gastrointestinal motility patterns. Experiments determining ICC origin and development in mice, chicken, and humans are described, as well as what is known in the zebrafish. At least six types of ICC in the digestive tract have been described and ICC heterogeneity in adult tissues is reviewed. Factors required for ICC development and for maintenance of ICC subclasses are described. This review is suitable for those new to ICC development and physiology, especially those focused on using zebrafish and other model systems.

The tRNA-histidine guanylyltransferase 1-like (THG1L), also known as induced in high glucose-1 (IHG-1), encodes for an essential mitochondria-associated protein highly conserved throughout evolution, that catalyses the 3'-5' addition of a guanine to the 5'-end of tRNA-histidine (tRNA^His). Previous data indicated that THG1L plays a crucial role in the regulation of mitochondrial biogenesis and dynamics, in ATP production, and is critically involved in the modulation of apoptosis, cell-cycle progression and survival, as well as in cellular stress responses and redox homeostasis. Dysregulations of THG1L expression play a central role in various pathologies, including nephropathies, and neurodevelopmental disorders often characterized by developmental delay and cerebellar ataxia. Despite the essential role of THG1L, little is known about its expression during vertebrate development. Herein, we examined the detailed spatio-temporal expression of this gene in the developing Xenopus laevis. Our results show that thg1l is maternally inherited and its temporal expression suggests a role during the earliest stages of embryogenesis. Spatially, thg1l mRNA localizes in the ectoderm and marginal zone mesoderm during early stages of development. Then, at tadpole stages, thg1l transcripts mostly localise in neural crests and their derivatives, somites, developing kidney and central nervous system, therefore largely coinciding with territories displaying intense energy metabolism during organogenesis in Xenopus.

Invertebrate and vertebrate species have many unusual cellular structures, such as long- or short-lived cell-in-cell structures and coenocytes. Coenocytes (often incorrectly described as syncytia) are multinuclear cells derived, unlike syncytia, not from the fusion of multiple cells but from multiple nuclear divisions without cytokinesis. An example of a somatic coenocyte is the coenocytic blastoderm in Drosophila. An astonishing property of coenocytes is the ability to differentiate the nuclei sharing a common cytoplasm into different subpopulations with different fate trajectories. An example of a germline coenocyte is the oogenic precursor of appendicularian tunicates, which shares many features with the somatic coenocyte of Drosophila. The germline coenocyte (coenocyst) is quite an unexpected structure because in most animals, including Drosophila, Xenopus, and mice, oogenesis proceeds within a group (cyst, nest) of sibling cells (cystocytes) connected by the intercellular bridges (ring canals, RCs) derived from multiple divisions with incomplete cytokinesis of a progenitor cell called the cystoblast. Here, I discuss the differences and similarities between cystocyte-based and coenocyst-based oogenesis, and the resemblance of coenocystic oogenesis to coenocytic somatic blastoderm in Drosophila. I also describe cell-in-cell structures that although not mechanistically, cytologically, or molecularly connected to somatic or germline coenocytes, are both unorthodox and intriguing cytological phenomena rarely covered by scientific literature.

During embryonic development, the vertebrate embryonic epiblast is divided into two parts including neural and superficial ectoderm. The neural plate border (NPB) is a narrow transitional area which locates between these parts and contains multipotent progenitor cells. Despite its small size, the cellular heterogeneity in this region produces specific differentiated cells. Signaling pathways, transcription factors, and the expression/repression of certain genes are directly involved in these differentiation processes. Different factors such as the Wnt signaling cascade, fibroblast growth factor (FGF), bone morphogenetic protein (BMP) signaling, and Notch, which are involved in various stages of the growth, proliferation, and differentiation of embryonic cells, are also involved in the determination and differentiation of neural plate border stem cells. Therefore, it is essential to consider the interactions and temporospatial coordination related to cells, tissues, and adjacent structures. This review examines our present knowledge of the formation of the neural plate border and emphasizes the requirement for interaction between different signaling pathways, including the BMP and Wnt cascades, the expression of its special target genes and their regulations, and the precise tissue crosstalk which defines the neural crest fate in the ectoderm at the early human embryonic stages.

Mutations in the gene encoding Tre2/Bub2/Cdc16 (TBC)1 domain family member 24 (TBC1D24) protein are associated with a variety of neurological disorders, ranging from non-syndromic hearing loss to drug-resistant lethal epileptic encephalopathy and DOORS syndrome [Deafness, Onychodystrophy, Osteodystrophy, intellectual disability (formerly referred to as mental Retardation), and Seizures]. TBC1D24 is a vesicle-associated protein involved in neural crest cell and neuronal migration, maturation, and neurotransmission. In the cochlea, TBC1D24 has been detected in auditory neurons, but few reliable and convergent data exist about the sensory epithelium. Here, the expression of TBC1D24 has been characterized via immunolabelling throughout the postnatal maturation of the mouse cochlear sensory epithelium. TBC1D24 was detected in glia-like non-sensory epithelial cells during early developmental stages. In contrast, TBC1D24 was virtually absent in adjacent sensory hair cells. This expression distinguishing non-sensory from sensory epithelial cells almost disappears around the onset of hearing. Until now, TBC1D24 was mainly described as a neuronal protein either in the brain or in the cochlea. The present observations suggest that TBC1D24 could also regulate vesicle trafficking in cochlear glia-like non-sensory epithelial cells. For a long time, research about epilepsy has been mainly neurocentric. However, there is now evidence proving that glial cell dysregulation contribute to pathogenesis of epilepsy and neurodevelopmental disorders. As a consequence, exploring the possibility that TBC1D24 could also have a role in glial cells of the central nervous system could help to gain insight into TBC1D24-related neurological pathogenesis.

Enhancers play an essential role in gene regulation by receiving cues from transcription factors and relaying these signals to modulate transcription from target promoters. Enhancer-promoter communications occur across large linear distances of the genome and with high specificity. The molecular mechanisms that underlie enhancer-mediated control of transcription remain unresolved. In this review, we focus on research in Drosophila uncovering the molecular mechanisms governing enhancer-promoter communication and discuss the current understanding of developmental gene regulation. The functions of protein acetylation, pausing of RNA polymerase II, transcriptional bursting, and the formation of nuclear hubs in the induction of tissue-specific programs of transcription during zygotic genome activation are considered.

Understanding the evolution of body plans has been one of the major areas of investigation in developmental and evolutionary biology. Cnidaria, the sister group to bilaterians, provides an opportunity to elucidate the origin and evolution of body axes. Hydra, a freshwater cnidarian, is a useful model to study signaling pathways governing pattern formation, which are conserved up to vertebrates including humans. The transforming growth factor β (TGF-β) signaling pathway is one of the fundamental pathways that regulate axis formation and organogenesis during embryonic development. In this article, we discuss the TGF-β pathway members identified in Hydra along with other cnidarians with an emphasis on bone morphogenetic proteins (BMPs) and their inhibitors. TGF-β members, especially those involved in BMP signaling pathway, are mainly involved in maintaining the Organizer region and patterning the body axis in Hydra. Identification of other members of this pathway in Hydra and fellow cnidarians would provide insights into the evolution of body axes and pattern formation in more complex metazoans.