Developmental Biology

SAM and SH3 domain-containing 1 (SASH1), a member of the Sly protein family, is a tumor suppressor gene that has been studied for its association with various cancers. SASH1 is highly expressed in the mammalian central nervous system, particularly in glial cells, and is expressed in the central nervous system during zebrafish embryo development. However, SASH1's role in brain development has rarely been investigated. In this study, Morpholino oligonucleotides (MO) were used to down-regulate sash1a expression in zebrafish to observe morphological changes in the brain...

The copepod species Acartia tonsa (Dana)(Crustacea) have the unique ability to induce quiescent embryonic dormancy if adverse environmental conditions occur; a characteristic shared by 41 other species belonging to the superfamily Centropagoida in the Calanoida order. However, the transcriptional changes characterizing this process are not known. Here, we compare the transcriptome of embryos in arrested quiescence with the normal development to identify pathways and differentially regulated transcripts involved in quiescent embryogenesis...

The Sonic hedgehog (SHh) signaling pathway is an imperative operating network that helps in regulates the critical events during the development processes like multicellular embryo growth and patterning. Disruptions in SHh pathway regulation can have severe consequences, including congenital disabilities, stem cell renewal, tissue regeneration, and cancer/tumor growth. Activation of the SHh signal occurs when SHh binds to the receptor complex of Patch (Ptc)-mediated Smoothened (Smo) (Ptc-smo), initiating downstream signaling...

Beclin1 (Becn1) is a multifunctional protein involved in autophagy regulation, membrane trafficking, and tumor suppression. In this study, we examined the roles of Becn1 in the pancreas development by generating mice with conditional deletion of Becn1 in the pancreas using pancreatic transcriptional factor 1a (Ptf1a)-Cre mice (Becn1f/f ; Ptf1aCre/+ ). Surprisingly, loss of Becn1 in the pancreas resulted in severe pancreatic developmental defects, leading to insufficient exocrine and endocrine pancreatic function...

A classic model for identification of novel differentiation mechanisms and pathways is the eye lens that consists of a monolayer of quiescent epithelial cells that are the progenitors of a core of mature fully differentiated fiber cells. The differentiation of lens epithelial cells into fiber cells follows a coordinated program involving cell cycle exit, expression of key structural proteins and the hallmark elimination of organelles to achieve transparency. Although multiple mechanisms and pathways have been identified to play key roles in lens differentiation, the entirety of mechanisms governing lens differentiation remain to be discovered...

Tissue development and regeneration are dynamic processes involving complex cell migration and cell-cell interactions. We have developed a protocol for complementary time-lapse and three-dimensional (3D) imaging of tissue for developmental and regeneration studies which we apply here to the zebrafish cardiac vasculature. 3D imaging of fixed specimens is used to first define the subject at high resolution then live imaging captures how it changes dynamically. Hearts from adult and juvenile zebrafish are extracted and cleaned in preparation for the different imaging modalities...

The Estrogen Related Receptor (ERR) nuclear hormone receptor genes have a wide diversity of roles in vertebrate development. In embryos, ERR genes are expressed in several tissues, including the central and peripheral nervous systems. Here we seek to establish the evolutionary history of chordate ERR genes, their expression and their regulation. We examine ERR expression in mollusc, amphioxus and sea squirt embryos, finding the single ERR orthologue is expressed in the nervous system in all three, with muscle expression also found in the two chordates...

The transcription factor ZFH-2 has well-documented roles in Drosophila neurogenesis and other developmental processes. Here we provide the first evidence that ZFH-2 has a role in oogenesis. We demonstrate that ZFH-2 is expressed in the wild-type ovary and that a loss of zfh-2 function produces a mutant ovary phenotype where egg chambers are reduced in number and fused. We also show that a loss of zfh-2 function can suppress a daughterless loss-of-function ovary phenotype suggesting a possible genetic relationship between these two genes in the ovary...

Understanding how cells activate intracellular signaling pathways in response to external signals, such as growth factors, is a longstanding goal of cell and developmental biology. Recently, live-cell signaling reporters have greatly expanded our understanding of signaling dynamics in response to wide-ranging stimuli and chemical or genetic perturbation, both ex vivo (cell lines) and in vivo (whole embryos or animals). Among the many varieties of reporter systems, translocation reporters that change sub-cellular localization in response to pathway activation have received considerable attention for their ease of use compared to FRET systems and favorable response times compared to transcriptional reporters...

No abstract text is available yet for this article.

Within the chordates, only some colonial ascidians experience whole body regeneration (WBR), where amputated small colonial fragments containing blood-vessels have the capability to regenerate the entire functional adult zooid within 1-3 weeks. Studying WBR in small colonial fragments taken at different blastogenic stages (the weekly developmental process characteristic to botryllid ascidians) from the ascidian Botrylloides leachii, about half of the fragments were able to complete regeneration (cWBR) three weeks following separation, about half were still in uncomplete, running regeneration (rWBR), and only a small percentage died...

Within the developing embryo is a microcosm of cell type diversity. Single cell RNA-sequencing (scRNA-seq) is used to reveal cell types, typically by grouping cells according to their gene regulatory states. However, both across and within these regulatory states are additional layers of cellular diversity represented by the differential expression of genes that govern cell function. Here, we analyzed scRNA-seq data representing the late gastrula stage of Strongylocentrotus purpuratus (purple sea urchin) to understand the patterning of transporters belonging to the ABC and SLC families...

Transmembrane p24 trafficking protein 10 (TMED10) is a conserved vesicle trafficking protein. It is dysregulated in Alzheimer disease and plays a pivotal role in the pathogenesis of Alzheimer disease. In addition to the brain, TMED10 is highly expressed in the exocrine pancreas; however, its biological functions and underlying mechanisms remain largely unknown. We studied reduced Tmed10 in zebrafish embryos by morpholino oligonucleotide knockdown and CRISPR-Cas9 mutagenesis. Tmed10-deficient embryos showed extensive loss of acinar mass and impaired acinar differentiation...

Craniofacial development is orchestrated by transcription factor-driven regulatory networks, epigenetic modifications, and signaling pathways. Signaling molecules and their receptors rely on endo-lysosomal trafficking to prevent accumulation on the plasma membrane. ESCRT (Endosomal Sorting Complexes Required for Transport) machinery is recruited to endosomal membranes enabling degradation of such endosomal cargoes. Studies in vitro and in invertebrate models established the requirements of the ESCRT machinery in membrane remodeling, endosomal trafficking, and lysosomal degradation of activated membrane receptors...

Tektins are a highly conserved family of coiled-coil domain containing proteins known to play a role in structure, stability and function of cilia and flagella. Tektin proteins are thought to form filaments which run the length of the axoneme along the inner surface of the A tubule of each microtubule doublet. Phylogenetic analyses suggest that the tektin family arose via duplications from a single tektin gene in a unicellular organism giving rise to four and five tektin genes in bilaterians and in spiralians, respectively...

Growth regulation must be robust to ensure correct final size, but also adaptative to adjust to less favorable environmental conditions. Developmental coordination between whole-organism and the brain is particularly important, as the brain is a critical organ with little adaptability. Brain growth mainly depends on neural stem cell (NSC) proliferation to generate differentiated neural cells, it is however unclear how organism developmental progression is coordinated with NSCs. Here we demonstrate that the steroid hormone ecdysone plays a multi-step, stage specific role in regulating Drosophila NSCs, the neuroblasts...

The external globus pallidus (GPe) is an essential component of the basal ganglia, a group of subcortical nuclei that are involved in control of action. Changes in the firing of GPe neurons are associated with both passive and active body movements. Aberrant activity of GPe neurons has been linked to motor symptoms of a variety of movement disorders, such as Parkinson's Disease, Huntington's disease and dystonia. Recent studies have helped delineate functionally distinct subtypes of GABAergic GPe projection neurons...

The evolution of jaws has played a major role in the success of vertebrate expansion into a wide variety of ecological niches. A fundamental, yet unresolved, question in craniofacial biology is about the origin of the premaxilla, the most distal bone present in the upper jaw of all amniotes. Recent reports have suggested that the mammalian premaxilla is derived from embryonic maxillary prominences rather than the frontonasal ectomesenchyme as previously shown in studies of chicken embryos. However, whether mammalian embryonic frontonasal ectomesenchyme contributes to the premaxillary bone has not been investigated and a tool to trace the contributions of the frontonasal ectomesenchyme to facial structures in mammals is lacking...

No abstract text is available yet for this article.

As the source of embryonic stem cells (ESCs), inner cell mass (ICM) can form all tissues of the embryo proper, however, its role in early human lineage specification remains controversial. Although a stepwise differentiation model has been proposed suggesting the existence of ICM as a distinct developmental stage, the underlying molecular mechanism remains unclear. In the present study, we perform an integrated analysis on the public human preimplantation embryonic single-cell transcriptomic data and apply a trajectory inference algorithm to measure the cell plasticity...