Developmental Dynamics[JOURNAL]
Sun
200 papers
Bridging maternal effects and epitranscriptomics: A novel perspective in developmental biology.
Ahi EP
Dev Dyn · 2025 Dec · PMID 41467365 · Publisher ↗
Maternal effects, encompassing both genetic (maternally expressed gene products) and non-genetic (maternal state) influences, are powerful determinants of offspring phenotype, yet their RNA-level mechanisms remain incomp...
Maternal effects, encompassing both genetic (maternally expressed gene products) and non-genetic (maternal state) influences, are powerful determinants of offspring phenotype, yet their RNA-level mechanisms remain incompletely resolved. In parallel, epitranscriptomics, an emerging field centered on chemical modifications to RNA, has revealed new layers of gene regulation with implications for cell fate, plasticity, and response to environmental cues. In this perspective article, a conceptual link is proposed between maternal effects and epitranscriptomic mechanisms, focusing on how maternal environments may shape offspring phenotypes through RNA modifications. Evidence is examined from diverse systems, including maternal deposition of modified RNAs, environmental modulation of RNA-modifying enzymes, and early developmental windows sensitive to maternal inputs. A clear distinction is drawn between placenta-mediated pathways that reprogram trophoblast/placental epitranscriptomics and direct fetal-tissue routes that act within developing organs. Although causal demonstrations are still emerging, convergent observations indicate that maternal environments can tune the offspring epitranscriptome with lasting phenotypic consequences. To articulate this emerging connection, the concept of "maternal RNA imprinting" is proposed, the idea that offspring development is shaped by maternal cues via targeted RNA modifications. This article aims not only to synthesize emerging insights across fields but also to stimulate interdisciplinary discussion and encourage investigation into the unexplored intersections of maternal biology and RNA regulation.
Mycn regulates vascular development through PI3K signaling pathway in zebrafish.
Zhao GQ, Cheng T, Wang PY … +7 more , Mo J, Yu F, Dong Y, Li YF, Feng Y, Xu PF, Shu LP
Dev Dyn · 2025 Dec · PMID 41439407 · Publisher ↗
BACKGROUND: Mycn, a MYC gene family member, is implicated in both carcinogenesis through amplification and Feingold syndrome through its deficiency. Previous studies have indicated that increased Mycn expression enhances...
BACKGROUND: Mycn, a MYC gene family member, is implicated in both carcinogenesis through amplification and Feingold syndrome through its deficiency. Previous studies have indicated that increased Mycn expression enhances vascularization in human neuroblastomas, yet its precise role in vascular development remains elusive. RESULTS: In this study, we utilized single-cell RNA-seq and live imaging analyses to confirm that mycn is expressed during zebrafish vasculogenesis. We investigated vascular development in zebrafish using a genetically engineered mycn mutation. Our findings reveal that mycn-deficient zebrafish exhibit reduced intersegmental vessels and malformed subintestinal vessels, primarily due to decreased cell proliferation in vascular endothelial cells. Importantly, we discovered that activation of PI3K signaling significantly ameliorates these vascular abnormalities. CONCLUSIONS: Our study establishes Mycn as a key regulator of vascular development in zebrafish, acting through the PI3K signaling pathway.
Non-migratory mode of ventral body wall closure: Primary mid-ventral covering is replaced by prospective definitive body wall.
Buma K, Takahashi Y
Dev Dyn · 2025 Dec · PMID 41431859 · Publisher ↗
BACKGROUND: During ventral body wall closure in amniotes, the skeleton and muscles such as sternum, ribs, and pectoral muscles undergo a striking positional change from the dorso-lateral to mid-ventral region. The precis...
BACKGROUND: During ventral body wall closure in amniotes, the skeleton and muscles such as sternum, ribs, and pectoral muscles undergo a striking positional change from the dorso-lateral to mid-ventral region. The precise process of ventral body wall closure has poorly been explored. We have presented and examined two opposing models: the invading closure model, in which musculoskeletal components infiltrate into the mid-ventral tissue, and the replacing closure model, in which the original mid-ventral tissue degenerates to be replaced by the dorso-lateral body wall. RESULTS: We developed a new method that enables direct cell labeling with PKH dyes in late chicken embryos. Our PKH labeling has shown that the original mid-ventral tissue, including both mesodermal and ectodermal cells, is progressively confined to the midline as the closure proceeds, contradicting the invading closure model. Moreover, the dorso-lateral tissue, including not only musculoskeletal but also non-musculoskeletal components, eventually contributes to the mid-ventral region. These results support the replacing closure model. CONCLUSION: The ventral body wall closure is achieved in a replacing manner. The mid-ventral region of the early body wall is a transient structure to cover the ventral surface, which is eventually eliminated to be replaced by the dorso-lateral region that represents the future definitive body wall.
Fhod3 in zebrafish supports myofibril stability during growth of embryonic skeletal muscle.
Russell A, Eng T, Amack JD … +1 more , Pruyne D
Dev Dyn · 2025 Dec · PMID 41416849 · Publisher ↗
BACKGROUND: Actin filament organization in cardiomyocytes critically depends on the formin Fhod3, but a role for Fhod3 in skeletal muscle development has not yet been described. RESULTS: We demonstrate here that in zebra...
BACKGROUND: Actin filament organization in cardiomyocytes critically depends on the formin Fhod3, but a role for Fhod3 in skeletal muscle development has not yet been described. RESULTS: We demonstrate here that in zebrafish mutated for one of two fhod3 paralog genes, fhod3a, skeletal muscle of the trunk appears normal through 2 days post-fertilization, but afterward exhibits myofibril damage, including gaps between myofibrils and myofibril fragmentation. Despite the progressive nature of the myofibril damage, fhod3a mutants differ from muscular dystrophy models in that damage is exacerbated by inhibition of muscle activity, and fhod3a mutants show no evidence of sarcolemma disruption. Rather, myofibril damage appears to coincide with growth of the contractile apparatus. We find neither the second fhod3 paralog, fhod3b, nor the related fhod1 contribute to embryonic skeletal muscle development, but fish individually mutated for fhod3a, fhod3b, or fhod1 are viable and appear grossly normal as adults. This may reflect redundancy in adults, as all three are expressed in many adult organs. CONCLUSIONS: These results indicate a fhod3-encoded formin is dispensable for initial myofibril assembly in skeletal muscle but promotes myofibril stability during muscle fiber growth. This is the first demonstration in a vertebrate that Fhod3 contributes to skeletal muscle development.
A comprehensive embryonic staging series of the turtle Trachemys scripta.
Noravian CM, Rand PG, Mahomed A … +4 more , Rickard A, Juvera OD, de Bellard ME, Ezin M
Dev Dyn · 2026 Mar · PMID 41327609 · Full text
BACKGROUND: Turtles hold a unique place in vertebrate evolutionary history, making them critical assets in embryology research. Yet, they remain understudied as potential model organisms in the field. Here, to support ex...
BACKGROUND: Turtles hold a unique place in vertebrate evolutionary history, making them critical assets in embryology research. Yet, they remain understudied as potential model organisms in the field. Here, to support experimental manipulations with turtle embryos, we have created a complete normal table of development for comprehensive embryonic staging of Trachemys scripta, one of the most common invasive turtle species worldwide. RESULTS: The development of T. scripta embryos from 0 days post-oviposition (DPO) to hatching (~60 DPO) was described from approximately 300 viable eggs collected at California State University, Northridge during the 2021-2024 nesting seasons. Thirty-one stages between oviposition and hatching were identified, and anatomical structures were cataloged using the Standard Event System (SES) chart. Morphological characteristics were imaged using bright-field microscopy and, for 4',6-diamidino-2-phenylindole-stained embryos, confocal microscopy. CONCLUSION: To facilitate further research with Chelonian embryos, this staging series blends previously accepted staging practices with new details of T. scripta gastrulation, SES criteria, and a photographic annotated glossary.
Single cell RNA seq of the major cell types in the larva of the sea star, Patiria miniata.
Oulhen N, Reyes G, Foster S … +1 more , Wessel G
Dev Dyn · 2025 Nov · PMID 41306072 · Publisher ↗
BACKGROUND: Echinoderms are invertebrate deuterostomes closely related to chordates and have become a tractable model for the study of the evolution of mechanisms involved in development, primordial germ cell specificati...
BACKGROUND: Echinoderms are invertebrate deuterostomes closely related to chordates and have become a tractable model for the study of the evolution of mechanisms involved in development, primordial germ cell specification, and regeneration. Sea urchins rely on inherited mechanisms for germline formation while sea stars rely instead on cell-cell inductive signaling mechanisms. RESULTS: Here, we present a single-cell RNA sequencing of the sea star Patiria miniata development (days 1, 2, 3, and 4 after fertilization). This resource focuses mainly on the day3 larva, but also presents an integrated dataset of the 4 days combined. We identified each cell cluster of the larva using marker genes for in situ RNA hybridization and found that, surprisingly, the primordial germ cells share many gene expression profiles with cells in the coelomic pouches, and that the ectodermal epithelium is quite heterogeneous. CONCLUSION: This dataset from the sea star provides a developmental trajectory of gene expression leading to each major cell type in the larva, providing a foundation for comparative analysis with other echinoderm species in parsing out mechanisms of developmental specification, regeneration, and germ line formation.
Additive effects on craniofacial development upon conditional ablation of PDGFRα and SHP2 in the mouse neural crest lineage.
Fuhr D, Johnston J, Brooks EP … +1 more , Fantauzzo KA
Dev Dyn · 2025 Nov · PMID 41246925 · Publisher ↗
BACKGROUND: Activity of the receptor tyrosine kinase PDGFRα and the tyrosine phosphatase SHP2 is critical for vertebrate craniofacial development. SHP2 has been shown to both positively and negatively regulate PDGFR sign...
BACKGROUND: Activity of the receptor tyrosine kinase PDGFRα and the tyrosine phosphatase SHP2 is critical for vertebrate craniofacial development. SHP2 has been shown to both positively and negatively regulate PDGFR signaling through the recruitment of Grb2 and dephosphorylation of the receptor, respectively. We sought to determine the effect of SHP2 binding to PDGFRα in the facial mesenchyme via phenotypic and biochemical analyses of an allelic series of mouse embryos with combined loss of both proteins in the neural crest lineage. RESULTS: We demonstrated that SHP2 preferentially binds PDGFRα/α homodimers among the three PDGFR dimers. We showed that double-homozygous mutant embryos exhibit a combination, but not an improvement or worsening, of the phenotypes observed upon conditional ablation of PDGFRα or SHP2 in the neural crest lineage. We further revealed that cell death in the lateral nasal and maxillary processes underlies the upper jaw phenotypes in embryos with loss of SHP2. Finally, we showed that E10.5 Pdgfra;Shp2;Wnt1-Cre embryos have increased phosphorylation of PDGFRα and the downstream effector Erk1/2 compared to control and double-heterozygous embryos. CONCLUSIONS: We propose a putative model in which SHP2 binds and dephosphorylates PDGFRα while simultaneously increasing survival through an Erk1/2-independent mechanism.
Biophysical processes of morphogenesis in lizard lungs.
Hill K, Griffing AH, Palmer MA … +7 more , Lemma B, Lupo AS, Gamble T, Shylo NA, Košmrlj A, Trainor PA, Nelson CM
Dev Dyn · 2025 Nov · PMID 41235677 · Publisher ↗
BACKGROUND: The lungs of squamate reptiles (lizards and snakes) are highly diverse, exhibiting single chambers, multiple chambers, transitional forms with two to three chambers, along with a suite of other anatomical fea...
BACKGROUND: The lungs of squamate reptiles (lizards and snakes) are highly diverse, exhibiting single chambers, multiple chambers, transitional forms with two to three chambers, along with a suite of other anatomical features, including finger-like epithelial projections into the body cavity known as diverticulae. During embryonic development of the simple, sac-like lungs of anoles, the epithelium is pushed through the openings of a pulmonary smooth muscle mesh by the forces of luminal fluid pressure. This process of stress ball morphogenesis generates the faveolar epithelium typical of squamate lungs. RESULTS: Here, we compared embryonic lung development in brown anoles, leopard geckos, and veiled chameleons to determine if stress ball morphogenesis is conserved across squamates and to understand the physical processes that generate transitional-chambered lungs with diverticulae. We found that epithelial protrusion through the holes in a pulmonary smooth muscle mesh is conserved across squamates. Surprisingly, however, we found that luminal inflation is not conserved. Instead, experimental and computational evidence suggests that leopard geckos and veiled chameleons may generate their faveolae via epithelial folding downstream of epithelial proliferation. Our data also suggest that the transitional chambers and diverticulae of veiled chameleon lungs may develop via apical constriction, a process known to be crucial for airway branching in the bird lung. CONCLUSIONS: Distinct morphogenetic mechanisms generate epithelial diversity in squamate lungs, which may underpin their species-specific physiological and ecological adaptations.
The association between neural crest-derived glia and melanocyte lineages throughout development and disease.
Kalcheim C
Dev Dyn · 2025 Nov · PMID 41216985 · Publisher ↗
Neural crest cells are a transient cell population that emerges from the dorsal neural tube during neurulation and migrates extensively throughout the embryo. Among their diverse derivatives, glial cells (such as Schwann...
Neural crest cells are a transient cell population that emerges from the dorsal neural tube during neurulation and migrates extensively throughout the embryo. Among their diverse derivatives, glial cells (such as Schwann and satellite ganglionic cells) and melanocytes represent two major lineages. In vitro studies suggested they share a common progenitor yet follow distinct differentiation pathways. Hence, neural crest cells must choose between glia and melanocyte fates-a decision crucial for forming the peripheral nervous and pigmentary systems. A groundbreaking discovery revealed that Schwann cell precursors along peripheral nerves serve as a secondary source of melanocytes during development. This finding challenged the traditional view that melanocytes arise exclusively from direct neural crest migration and demonstrated remarkable plasticity in the glial lineage. This glia/melanocyte fate choice represents a well-characterized example of binary fate decisions in vertebrate development, involving complex interactions between transcriptional networks, signaling pathways, and environmental cues. Importantly, the glia/melanocyte decision has implications for cancer and injury-induced plasticity, where embryonic pathways may be reactivated. For example, during melanomagenesis, cells can exhibit both melanocytic and glial features. Understanding how neural crest cells decide between glial and melanocyte fates may offer new insights for regenerative medicine and cancer therapy.
Mathematical modeling predicts novel mechanisms of stream confinement from Trail/Colec12/Dan in the collective migration of cranial neural crest cells.
Johnson SWS, Kulesa PM, Baker RE … +1 more , Maini PK
Dev Dyn · 2026 Jan · PMID 41201178 · Full text
BACKGROUND: In vertebrate embryogenesis, cranial neural crest cells (CNCCs) migrate along discrete pathways. Analyses in the chick have identified key molecular candidates for the confinement of CNCC migration to stereot...
BACKGROUND: In vertebrate embryogenesis, cranial neural crest cells (CNCCs) migrate along discrete pathways. Analyses in the chick have identified key molecular candidates for the confinement of CNCC migration to stereotypical pathways as Colec12, Trail, and Dan. The effects of these factors on CNCCs in vitro are known, but how they confine migration to discrete streams in vivo remains poorly understood. Here, we propose and test several hypothetical mechanisms by which these factors confine cell streams and maintain coherent migration, simulating an expanded agent-based model for collective CNCC migration. RESULTS: Model simulations suggest that Trail enhances adhesion between CNCCs, facilitating movement towards stereotypical migratory pathways, whereas Colec12 confines CNCCs by inducing longer, branched filopodia that facilitate movement down Colec12 gradients and re-connections with streams. Moreover, we find that Trail and Colec12 facilitate the exchange of CNCCs and the formation of CNCC bridges between adjacent streams that are observed in vivo but poorly understood mechanistically. Finally, we predict that Dan increases the coherence of streams by modulating the speed of CNCCs at the leading edge of collectives to prevent escape. CONCLUSIONS: Our work highlights the importance of Trail, Colec12, and Dan in CNCC migration and predicts novel mechanisms for the confinement of CNCCs to stereotypical pathways in vivo.
An optimized, high-throughput workflow for the collection, processing, and visualization of histology data in comparative vertebrate morphogenesis.
Gensbigler PA, Foster W, Kiemen AL … +1 more , Bever GS
Dev Dyn · 2025 Oct · PMID 41165208 · Publisher ↗
In an era where the diversity and quality of imaging modalities is rapidly increasing, it may seem counterintuitive to promote classical histology as a critical skill. It is a mistake, however, to assume that the heurist...
In an era where the diversity and quality of imaging modalities is rapidly increasing, it may seem counterintuitive to promote classical histology as a critical skill. It is a mistake, however, to assume that the heuristic potential of these high-resolution histological data is stagnant. Deep learning algorithms have emerged as an efficient tool for converting and quantifying the cellular resolution of 2D histology sections as detailed 3D models, capable of being integrated with a diversity of multi-omics data. Such analytical innovation requires large numbers of high-quality slides whose construction faces a variety of technical challenges. These challenges are exaggerated for developmental and evolutionary biologists, for whom ontogeny and phylogeny are critical variables that require additional sampling. Our goal is to provide a protocol optimized for the thin-section histology of vertebrate embryos, detailing best practices for sample collection, processing, and slide preparation. We hope that by: (1) synthesizing a scattered methodological literature that often excludes embryological tissues, and (2) recommending adjustments to common techniques like dehydration, xylene infiltration, and sectioning, other researchers may bypass the frustrating and time-consuming problems we encountered and move quickly to producing the high-quality histological data that modern developmental biology is likely to demand.
The segregation of Calb1, Calb2, and Prph neurons reveals distinct and mixed neuronal populations and projections to hair cells in the inner ear and central nuclei.
Lee JH, Yamoah EN, Kersigo J … +4 more , Elliott K, LaRoda N, Pavlinkova G, Fritzsch B
Dev Dyn · 2025 Oct · PMID 41165193 · Full text
BACKGROUND: Knockin mouse models expressing calbindin (Calb1), calretinin (Calb2), and peripherin (Prph) exhibit changes in hair cells (HCs), spiral ganglion neurons (SGN), vestibular ganglion neurons (VGNs), and their c...
BACKGROUND: Knockin mouse models expressing calbindin (Calb1), calretinin (Calb2), and peripherin (Prph) exhibit changes in hair cells (HCs), spiral ganglion neurons (SGN), vestibular ganglion neurons (VGNs), and their central projections. RESULTS: Developing cristae HCs show strong Calb1-positive expression, but adult HCs are mainly Calb2-positive. Utricle and saccule initially have Calb2-positive HCs and later develop Calb1-positive HCs in the striola region. Inner hair cells (IHCs) and outer hair cells (OHCs) in the cochlea express Calb2 early on. Calb1 expression in OHCs overlaps with Calb2; the expression of Myo7a, Calb1, and Calb2 reaches the apex later. SGNs and VGNs exhibit distinct Calb1 and Calb2 patterns but include a subpopulation with mixed expression. Central fibers are Calb1- and Calb2-positive early in the developing cochlear nuclei (CN) and vestibular nuclei (VN) but remain highly Prph-positive. VGNs innervate the lateral and VN, which are positive for Calb2 and Prph. Distinct Calb1-positive neurons overlap with the anterior (A) and ventral (V) cochlear nuclei (AVCN, PVCN) with Calb2, while the dorsal cochlear nucleus (DCN) shows segregation of Calb2 and Calb1. CONCLUSION: We offer insights into the timing of how neuronal identity and connectivity are regulated in the auditory and vestibular systems, as shown by the expression of Calb1, Calb2, and Prph.
Correction to "Heparan sulfate proteoglycan expression in the regenerating zebrafish fin".
Dev Dyn · 2026 Jan · PMID 41163528 · Publisher ↗
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The β integrin modulates serotonin sensitivity via NPxY motifs to regulate egg laying and mechanosensation behaviors in Caenorhabditis elegans.
Bumm JH, Lee DD, Qiu Z … +5 more , Choi AH, Kolluri M, Olsen MJ, Wang L, Lee M
Dev Dyn · 2025 Oct · PMID 41117756 · Publisher ↗
BACKGROUND: Integrin is an αβ heterodimeric receptor to the extracellular matrix; its binding to the matrix recruits focal adhesions to two NPxY motifs, the tyrosine phosphorylation sites in the cytoplasmic domain. Studi...
BACKGROUND: Integrin is an αβ heterodimeric receptor to the extracellular matrix; its binding to the matrix recruits focal adhesions to two NPxY motifs, the tyrosine phosphorylation sites in the cytoplasmic domain. Studies found that replacing tyrosines (Y) with phenylalanines (F) in the motif of β1 integrin displayed little developmental or behavioral defects. However, the tyrosine-to-alanine (A) caused embryonic lethality. RESULTS: Here we report novel functions of the NPxY motifs in Caenorhabditis elegans pat-3 β integrin. The membrane-proximal non-phosphorylation pat-3(Y792F) mutation caused hypersensitive egg laying in serotonin, which is more prominent than the membrane-distal NPxY. The double non-phosphorylatable pat-3(YYFF) mutant exhibited serotonin hypersensitivity and defective egg retention. The phosphomimetic NPxY, pat-3(Y804E), mutant displayed reduced egg laying in response to serotonin and fluoxetine, suggesting that the NPxY phosphorylation is associated with vulval contraction and serotonin sensitivity. Additionally, pat-3(Y792A), pat-3(Y792F), pat-3(Y804E), and pat-3(YYFF) mutants exhibited mechanosensation defects, demonstrating that NPxY phosphorylation regulates sensory neuron activity. Further analysis revealed that exogenous serotonin reduced mechanosensation, while blocking serotonin secretion rescued the mechanosensation of pat-3 NPxY mutants, suggesting that integrin NPxY modulates serotonin levels in C. elegans. CONCLUSION: Our results underscore the functional importance of pat-3 NPxY motifs in muscle and neurons, potentially linking integrin NPxY motifs to neurotransmitter response and mechanosensory functions.
Commensal skin bacteria interact with the innate immune system to promote tail regeneration in Xenopus laevis tadpoles.
Chapman PA, Day RC, Hudson DT … +3 more , Ward JM, Morgan XC, Beck CW
Dev Dyn · 2025 Oct · PMID 41104769 · Publisher ↗
BACKGROUND: Tadpoles of the clawed frog Xenopus laevis can regenerate their tails following partial amputation, replacing the missing spinal cord, muscles, and fin. However, for a brief period of development this respons...
BACKGROUND: Tadpoles of the clawed frog Xenopus laevis can regenerate their tails following partial amputation, replacing the missing spinal cord, muscles, and fin. However, for a brief period of development this response becomes unstable, leading to a proportion of tadpoles that undergo wound healing rather than regenerative programme. Inspired by a growing number of links between the microbiome and human inflammatory disease, we asked how the tadpole skin microbiome and innate immunity influence the regeneration of a complex appendage. We previously showed that tadpoles raised in antibiotics such as gentamicin or penicillin/streptomycin or with reduced Toll-like receptor 4 signaling regenerated tails poorly, while adding exogenous lipopolysaccharide promoted or rescued tail regeneration. RESULTS: Here, we show that CRISPR/Cas9 knockdown of Toll-like receptor 2 also reduces tadpole tail regeneration. Conversely, addition of the pathogen-associated molecular pattern peptidoglycan to the medium at the time of amputation increases the likelihood of regeneration. While we have previously shown that tadpoles acquire most of their early skin microbiome from their mothers, analysis of mitochondrial haplotypes did not support a genetic maternal explanation of regenerative bias. Levels of endogenous lipopolysaccharides on tail tips were also not predictive of regenerative success, and shotgun sequencing indicated that there was no difference in bacterial loads. To see if the composition of native microbiome was associated with regenerative success, we sequenced the 16S rRNA genes of 503 tadpole tail tips from 12 sibships and mapped these to the regenerative outcome of each tadpole. While no one taxon was found to be associated with regenerative success, higher proportions of Gram-positive genera overall correlated with improved regeneration outcomes. Supporting this finding, when tadpoles were raised with the antibiotic vancomycin, to select against Gram-positive bacteria, the number of individuals undergoing tail regeneration was significantly decreased. CONCLUSIONS: Taken together, our results suggest a previously undocumented role for Tlr2, possibly activated by peptidoglycan from Gram-positive commensal skin bacteria, in tipping the balance from wound repair to regenerative programmes in Xenopus laevis refractory stage tadpoles.
Modest alterations in Drosophila denticle morphology reveal genetic interactions between actin disassembly proteins and ck/Myosin VIIA.
Boettcher A, Jones H, Leskovec M … +3 more , Majer H, Allen B, Sallee J
Dev Dyn · 2025 Oct · PMID 41081539 · Publisher ↗
BACKGROUND: Building and disassembling actin filaments is essential for the remodeling of the actin cytoskeleton. In large structures, like Drosophila bristles, the loss of function of actin disassembly proteins can lead...
BACKGROUND: Building and disassembling actin filaments is essential for the remodeling of the actin cytoskeleton. In large structures, like Drosophila bristles, the loss of function of actin disassembly proteins can lead to smaller and misshapen bundled actin. Here we investigate whether mutant alleles of the disassembly genes twinstar (tsr), flare (flr), and twinfilin (twf) show similar phenotypes in smaller embryonic actin-based denticles. We also examined potential genetic interactions between F-actin disassembly proteins and the molecular motor ck/myosin VIIA, a protein necessary for denticle formation. RESULTS: Cuticle preparations of late-stage embryos were examined for denticle hook orientation, height, and width. There were mild morphological phenotypes such as loss of hook polarity across the genes. Single mutants for the disassembly genes showed that loss of tsr caused denticles to be longer, loss of twf resulted in shorter denticles, and mutant flr alleles showed varied effects. Double mutants of tsr and twf showed a genetic interaction in widths of denticles while ck was epistatic to twf and flr for width. CONCLUSION: These results demonstrate that actin disassembly proteins and ck/myosin VIIA are involved in denticle formation, and the lack of wild type gene function in tsr, twf, flr, and ck causes measurable defects in denticle morphology.
Expression of mutant TIE2 p.L914F during mouse development causes embryonic lethality and defects in vascular remodeling.
Bischoff LJ, Schrenk S, Soroko K … +4 more , Sherpa C, Arasu A, Reynaud D, Boscolo E
Dev Dyn · 2025 Oct · PMID 41074681 · Full text
BACKGROUND: Sporadic venous malformation (VM) is associated with the hyperactivating p.L914F mutation in TIE2, a receptor tyrosine kinase essential for vascular development. This mutation is not found in hereditary VM, s...
BACKGROUND: Sporadic venous malformation (VM) is associated with the hyperactivating p.L914F mutation in TIE2, a receptor tyrosine kinase essential for vascular development. This mutation is not found in hereditary VM, suggesting incompatibility with life when expressed during early vascular development. Therefore, we utilized a genetic mouse model that expresses TIE2 p.L914F to determine its phenotypical effects during development. RESULTS: B6-Tg(Rosa26-TIE2) (TIE2) mice were generated and then validated for the presence of the transgene. The constitutive endothelial-specific Tie2-Cre line was used to activate expression of the mutant gene during early embryonic development. Tie2-Cre;TIE2 embryos experienced lethality at approximately embryonic day (E)9.5. Three-dimensional imaging of embryos and yolk sacs revealed impaired vascular remodeling in mutant animals, resulting in malformed vasculature with disorganized, dilated, and non-functional blood vessels. The abnormal yolk sac vascular phenotype was not associated with total loss of erythroid cells or increased cell proliferation. CONCLUSIONS: The TIE2 mice used in this study represent a novel genetic model of TIE2 p.L914F-driven vascular disease. This study provides the first experimental evidence that this mutation is incompatible with early prenatal development due to its deleterious effects on the vasculature, illustrating the vital role of balanced TIE2 signaling during vessel development and remodeling.
Cryopreservation of sea urchin (Lytechinus pictus) embryos and development through metamorphosis.
Vacquier VD, Hamdoun A
Dev Dyn · 2025 Oct · PMID 41070784 · Publisher ↗
BACKGROUND: Sea urchins have contributed to knowledge of fertilization, embryonic development, and cell physiology for 150 years. Their evolutionary position, as basal deuterostomes, and their long background in developm...
BACKGROUND: Sea urchins have contributed to knowledge of fertilization, embryonic development, and cell physiology for 150 years. Their evolutionary position, as basal deuterostomes, and their long background in developmental biology motivate establishing a genetically enabled sea urchin species. Because of its relatively short generation time of 4-6 months and ease of culture, our lab has focused on the California sea urchin Lytechinus pictus as a multigenerational model and produced knockout and transgenic lines using this species. To ensure that diverse genetic lines can be preserved, methods must be developed to cryopreserve gametes and embryos. We have previously reported methods for cryopreservation of sperm, but robust methods to preserve embryos remain lacking. RESULTS: Here, we describe a relatively simple method to cryopreserve late gastrulae embryos of L. pictus. Importantly, we show that, after thawing and culturing, the embryos progress through larval development, undergo metamorphosis, and yield juvenile adults, indicating the method is robust. CONCLUSION: The cryopreservation of embryos is an important advance that will facilitate the biobanking, sharing, and long-term preservation of diverse genetic lines. This method may also eventually prove useful for cryopreservation of embryos of other marine invertebrates.
Multiple gene knockouts in newts reveal novel functions of 5' Hox genes in limb development along the anterior-posterior and proximal-distal axes.
Urakawa K, Ito Y, Matsubara H … +6 more , Suzuki KT, Matsunami M, Shigenobu S, Hayashi T, Abe G, Takeuchi T
Dev Dyn · 2025 Sep · PMID 41020479 · Publisher ↗
BACKGROUND: 5' Hox genes play crucial roles in limb patterning along the proximal-distal and anterior-posterior axes in mice. However, their functional conservation across tetrapods remains unclear. We previously found t...
BACKGROUND: 5' Hox genes play crucial roles in limb patterning along the proximal-distal and anterior-posterior axes in mice. However, their functional conservation across tetrapods remains unclear. We previously found that newt Hox13 is essential for digit formation during both development and regeneration. In contrast, the functions of other 5' Hox genes (Hox9-Hox12) in newts remain u[WLYJ-108]nknown. Therefore, we generated 5' Hox knockout newts (Pleurodeles waltl) using CRISPR-Cas9. RESULTS: Individual knockouts of Hox9, Hox10, and Hox12 disrupted all respective paralogs; however, these newts displayed no apparent abnormalities in limb skeletons. In contrast, Hox11 knockout newts exhibited skeletal defects in the posterior zeugopod and autopod of both the forelimbs and hindlimbs. Moreover, compound knockouts of Hox9 and Hox10 caused substantial loss of stylopod and anterior zeugopod/autopod elements specifically in the hindlimbs. CONCLUSION: These findings indicate that Hox9 and Hox10 redundantly regulate stylopod formation in the hindlimbs. Furthermore, Hox9/Hox10 and Hox11 contribute to the development of the anterior and posterior regions of the zeugopod/autopod in the hindlimbs, respectively. These novel roles of 5' Hox genes identified in newts suggest the functional diversification of 5' Hox genes in tetrapod limb development.
Gene expression detection methods in the African turquoise killifish brain.
Whisenant E, Lekven AC
Dev Dyn · 2025 Sep · PMID 41002004 · Publisher ↗
BACKGROUND: The short-lived African turquoise killifish (Nothobranchius furzeri) is an important emerging model organism for gene expression studies, with limited tools for transcript and protein detection, especially me...
BACKGROUND: The short-lived African turquoise killifish (Nothobranchius furzeri) is an important emerging model organism for gene expression studies, with limited tools for transcript and protein detection, especially methods that are both cost-effective and high-resolution. Brain tissue is particularly challenging to analyze due to its opacity and structural complexity, making whole-organ imaging techniques valuable. However, various tissue-clearing protocols adapted for N. furzeri are long and require specialized equipment. RESULTS: To address these limitations for gene expression detection techniques, we optimized cryosection-compatible ISH protocols for mRNA detection and adapted the EZ-clear method for whole-brain protein visualization in N. furzeri. Using Gfap and Dat as test markers, we optimized the colorimetric ISH protocol for detecting mRNA in both thick and thin sections, achieved high signal-to-noise ratios, and confirmed expression in expected brain regions. Additionally, we adapted the EZ-clear protocol for brain tissue clearing. We demonstrate the method's compatibility with immunostaining, showing a possible upregulation in Gfap, alongside endogenous fluorescence preservation of transgenic reporter lines. CONCLUSIONS: Our protocols add to the existing cost-effective and accessible methods for gene and protein visualization in N. furzeri. The cryosection-amenable ISH and adapted EZ-clear protocols expand the methodological toolkit for studying gene expression in this emerging model system.
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