Hertwig's rule states that cells divide along their longest axis, usually driven by forces acting on the mitotic spindle. Here, we show that in contrast to this rule, microtubule-based pulling forces in early Caenorhabditis elegans embryos align the spindle with the short axis of the cell. We combine theory with experiments to reveal that in order to correct this misalignment, inward forces generated by the constricting cytokinetic ring rotate the entire cell until the spindle is aligned with the cell's long axis. Experiments with slightly compressed mouse zygotes indicate that this cytokinetic ring-driven mechanism of ensuring Hertwig's rule is general for cells capable of rotating inside a confining shell, a scenario that applies to early cell divisions of many systems.

• Klíčová slova
• actomyosin, biophysics, cell biology, cytokinesis, development,
• MeSH
• aparát dělícího vřeténka * metabolismus   MeSH
• biologické modely MeSH
• Caenorhabditis elegans * embryologie   MeSH
• cytokineze fyziologie   MeSH
• embryo nesavčí cytologie   MeSH
• embryonální vývoj fyziologie   MeSH
• mikrotubuly metabolismus   MeSH
• myši MeSH
• rotace MeSH
• zvířata MeSH
• zygota metabolismus   cytologie   růst a vývoj   MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The cranial neural crest (CNC) arises within the developing central nervous system, but then migrates away from the neural tube in three consecutive streams termed mandibular, hyoid and branchial, respectively, according to the order along the anteroposterior axis. While the process of neural crest emigration generally follows a conserved anterior to posterior sequence across vertebrates, we find that ray-finned fishes (bichir, sterlet, gar, and pike) exhibit several heterochronies in the timing and order of CNC emergence that influences their subsequent migratory patterns. First, emigration of the cranial neural crest in these fishes occurs prematurely compared to other vertebrates, already initiating during early neurulation and well before neural tube closure. Second, delamination of the hyoid stream occurs prior to the more anterior mandibular stream; this is associated with early morphogenesis of key hyoid structures like external gills (bichir), a large opercular flap (gar) or first forming cartilage (pike). In sterlet, the hyoid and branchial CNC cells form a single hyobranchial sheet, which later segregates in concert with second pharyngeal pouch morphogenesis. Taken together, the results show that despite generally conserved migratory patterns, heterochronic alterations in the timing of emigration and pattern of migration of CNC cells accompanies morphological diversity of ray-finned fishes.

• Klíčová slova
• Craniofacial, Evolution, Neural crest, Neurulation, Vertebrates,
• MeSH
• biologická evoluce * MeSH
• crista neuralis cytologie   embryologie   MeSH
• embryo nesavčí cytologie   embryologie   MeSH
• pohyb buněk fyziologie   MeSH
• ryby embryologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

BACKGROUND: The study of the mechanisms controlling wound healing is an attractive area within the field of biology, with it having a potentially significant impact on the health sector given the current medical burden associated with healing in the elderly population. Healing is a complex process and includes many steps that are regulated by coding and noncoding RNAs, proteins and other molecules. Nitric oxide (NO) is one of these small molecule regulators and its function has already been associated with inflammation and angiogenesis during adult healing. RESULTS: Our results showed that NO is also an essential component during embryonic scarless healing and acts via a previously unknown mechanism. NO is mainly produced during the early phase of healing and it is crucial for the expression of genes associated with healing. However, we also observed a late phase of healing, which occurs for several hours after wound closure and takes place under the epidermis and includes tissue remodelling that is dependent on NO. We also found that the NO is associated with multiple cellular metabolic pathways, in particularly the glucose metabolism pathway. This is particular noteworthy as the use of NO donors have already been found to be beneficial for the treatment of chronic healing defects (including those associated with diabetes) and it is possible that its mechanism of action follows those observed during embryonic wound healing. CONCLUSIONS: Our study describes a new role of NO during healing, which may potentially translate to improved therapeutic treatments, especially for individual suffering with problematic healing.

• Klíčová slova
• AP-1, Leptin, Nitric oxide, RNA-sequencing, Transcriptome, Wound healing, Xenopus laevis,
• MeSH
• embryo nesavčí cytologie   metabolismus   fyziologie   MeSH
• glukosa metabolismus   MeSH
• hojení ran * MeSH
• leptin metabolismus   MeSH
• oxid dusnatý metabolismus   MeSH
• regulace genové exprese MeSH
• signální transdukce MeSH
• Xenopus laevis MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glukosa MeSH
• leptin MeSH
• oxid dusnatý MeSH

The epithalamic region of fishes shows prominent left-right asymmetries that are executed by nodal signaling upstream of the asymmetry-determining transcription factor pitx2. Previous reports have identified that nodal controls the left-sided pitx2 expression in the lateral plate mesoderm through an enhancer present in the last intron of this gene. However, whether similar regulation occurs also in the case of epithalamic asymmetry is currently unresolved. Here, we address some of the cis-regulatory information that control asymmetric pitx2 expression in epithalamus by presenting a Tg(pitx2:EGFP) 116-17 transgenic medaka model, which expresses enhanced green fluorescent protein (EGFP) under control of an intronic enhancer. We show that this transgene recapitulates epithalamic expression of the endogenous pitx2 and that it responds to nodal signaling inhibition. Further, we identify that three foxh1-binding sites present in this enhancer modulate expression of the transgene and that the second site is absolutely necessary for the left-sided epithalamic expression while the other two sites may have subtler regulative roles. We provide evidence that left-sided epithalamic pitx2 expression is controlled through an enhancer present in the last intron of this gene and that the regulatory logic underlying asymmetric pitx2 expression is shared between epithalamic and lateral plate mesoderm regions.

• Klíčová slova
• Asymmetry, Enhancer, Epithalamus, Medaka, Transgene, pitx2,
• MeSH
• embryo nesavčí cytologie   metabolismus   MeSH
• epitalamus embryologie   metabolismus   MeSH
• forkhead transkripční faktory genetika   metabolismus   MeSH
• funkční lateralita MeSH
• homeoboxový protein PITX2 MeSH
• homeodoménové proteiny genetika   metabolismus   MeSH
• introny * MeSH
• mezoderm embryologie   metabolismus   MeSH
• Oryzias embryologie   genetika   MeSH
• protein nodal genetika   metabolismus   MeSH
• signální transdukce MeSH
• transgeny genetika   MeSH
• transkripční faktory genetika   metabolismus   MeSH
• vazebná místa MeSH
• vývojová regulace genové exprese * MeSH
• zelené fluorescenční proteiny genetika   metabolismus   MeSH
• zesilovače transkripce * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• enhanced green fluorescent protein MeSH Prohlížeč
• forkhead transkripční faktory MeSH
• homeodoménové proteiny MeSH
• protein nodal MeSH
• transkripční faktory MeSH
• zelené fluorescenční proteiny MeSH

Establishment of asymmetry along the left-right (LR) body axis in vertebrates requires interplay between Nodal and Bmp signaling pathways. In the basal chordate amphioxus, the left-sided activity of the Nodal signaling has been attributed to the asymmetric morphogenesis of paraxial structures and pharyngeal organs, however the role of Bmp signaling in LR asymmetry establishment has not been addressed to date. Here, we show that Bmp signaling is necessary for the development of LR asymmetric morphogenesis of amphioxus larvae through regulation of Nodal signaling. Loss of Bmp signaling results in loss of the left-sided expression of Nodal, Gdf1/3, Lefty and Pitx and in gain of ectopic expression of Cerberus on the left side. As a consequence, the larvae display loss of the offset arrangement of axial structures, loss of the left-sided pharyngeal organs including the mouth, and ectopic development of the right-sided organs on the left side. Bmp inhibition thus phenocopies inhibition of Nodal signaling and results in the right isomerism. We conclude that Bmp and Nodal pathways act in concert to specify the left side and that Bmp signaling plays a fundamental role during LR development in amphioxus.

• Klíčová slova
• Amphioxus, Bmp signaling, Left-right asymmetry, Mouth, Nodal pathway,
• MeSH
• embryo nesavčí cytologie   embryologie   MeSH
• faktory určující pravo-levou symetrii biosyntéza   MeSH
• kopinatci cytologie   embryologie   MeSH
• kostní morfogenetické proteiny metabolismus   MeSH
• protein nodal metabolismus   MeSH
• signální transdukce fyziologie   MeSH
• vývojová regulace genové exprese fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• faktory určující pravo-levou symetrii MeSH
• kostní morfogenetické proteiny MeSH
• protein nodal MeSH

The parental genomes are initially spatially separated in each pronucleus after fertilization. Here we have used green-to-red photoconversion of Dendra2-H2B-labeled pronuclei to distinguish maternal and paternal chromatin domains and to track their spatial distribution in living Caenorhabditis elegans embryos starting shortly after fertilization. Intermingling of the parental chromatin did not occur until after the division of the AB and P1 blastomeres, at the 4-cell stage. Unexpectedly, we observed that the intermingling of chromatin did not take place during mitosis or during chromatin decondensation, but rather ∼ 3-5 minutes into the cell cycle. Furthermore, unlike what has been observed in mammalian cells, the relative spatial positioning of chromatin domains remained largely unchanged during prometaphase in the early C. elegans embryo. Live imaging of photoconverted chromatin also allowed us to detect a reproducible 180° rotation of the nuclei during cytokinesis of the one-cell embryo. Imaging of fluorescently-labeled P granules and polar bodies showed that the entire embryo rotates during the first cell division. To our knowledge, we report here the first live observation of the initial separation and subsequent mixing of parental chromatin domains during embryogenesis.

• MeSH
• blastomery cytologie   metabolismus   MeSH
• buněčný cyklus MeSH
• Caenorhabditis elegans embryologie   genetika   metabolismus   MeSH
• časosběrné zobrazování metody   MeSH
• časové faktory MeSH
• chromatin genetika   metabolismus   MeSH
• embryo nesavčí cytologie   embryologie   metabolismus   MeSH
• fertilizace MeSH
• histony genetika   metabolismus   MeSH
• luminescentní proteiny genetika   metabolismus   MeSH
• mitóza MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• chromatin MeSH
• histony MeSH
• luminescentní proteiny MeSH

BACKGROUND: Lineage tracing has shown that most of the facial skeleton is derived from cranial neural crest cells. However, the local signals that influence postmigratory, neural crest-derived mesenchyme also play a major role in patterning the skeleton. Here, we study the role of BMP signaling in regulating the fate of chondro-osteoprogenitor cells in the face. RESULTS: A single Noggin-soaked bead inserted into stage 15 chicken embryos induced an ectopic cartilage resembling the interorbital septum within the palate and other midline structures. In contrast, the same treatment in stage 20 embryos caused a loss of bones. The molecular basis for the stage-specific response to Noggin lay in the simultaneous up-regulation of SOX9 and downregulation of RUNX2 in the maxillary mesenchyme, increased cell adhesiveness as shown by N-cadherin induction around the beads and increased RA pathway gene expression. None of these changes were observed in stage 20 embryos. CONCLUSIONS: These experiments demonstrate how slight changes in expression of growth factors such as BMPs could lead to gain or loss of cartilage in the upper jaw during vertebrate evolution. In addition, BMPs have at least two roles: one in patterning the skull and another in regulating the skeletogenic fates of neural crest-derived mesenchyme. Developmental Dynamics 245:947-962, 2016. © 2016 Wiley Periodicals, Inc.

• Klíčová slova
• Noggin, cartilage, cell fate, chicken embryo, chondro-osteoprogenitor, frontonasal mass, interorbital septum, maxillary,
• MeSH
• embryo nesavčí cytologie   metabolismus   MeSH
• kmenové buňky cytologie   metabolismus   fyziologie   MeSH
• kostní morfogenetické proteiny genetika   metabolismus   MeSH
• kuřecí embryo MeSH
• mezoderm cytologie   metabolismus   fyziologie   MeSH
• obličej embryologie   MeSH
• signální transdukce účinky léků   MeSH
• transkripční faktor SOX9 genetika   metabolismus   MeSH
• transportní proteiny farmakologie   MeSH
• vývojová regulace genové exprese genetika   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• kuřecí embryo MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kostní morfogenetické proteiny MeSH
• noggin protein MeSH Prohlížeč
• transkripční faktor SOX9 MeSH
• transportní proteiny MeSH

Primordial germ cells (PGCs) arise elsewhere in the embryo and migrate into developing gonadal ridges during embryonic development. In several model animals, formation and migration patterns of PGCs have been studied, and it is known that these patterns vary. Sturgeons (genus Acipenser) have great potential for comparative and evolutionary studies of development. Sturgeons belong to the super class Actinoptergii, and their developmental pattern is similar to that of amphibians, although their phylogenetic position is an out-group to teleost fishes. Here, we reveal an injection technique for sturgeon eggs allowing visualization of germplasm and PGCs. Using this technique, we demonstrate that the PGCs are generated at the vegetal pole of the egg and they migrate on the yolky cell mass toward the gonadal ridge. We also provide evidence showing that PGCs are specified by inheritance of maternally supplied germplasm. Furthermore, we demonstrate that the migratory mechanism is well-conserved between sturgeon and other remotely related teleosts, such as goldfish, by a single PGCs transplantation (SPT) assay. The mode of PGCs specification in sturgeon is similar to that of anurans, but the migration pattern resembles that of teleosts.

• MeSH
• biologické modely * MeSH
• embryo nesavčí cytologie   embryologie   MeSH
• embryonální vývoj fyziologie   MeSH
• pohyb buněk fyziologie   MeSH
• ryby embryologie   MeSH
• zárodečné buňky cytologie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVES: Malathion is generally not classified as toxic. However, the toxicity seems to be species-dependent. Local and systemic toxicity data for birds are rare, but a decrease of wild bird densities in areas where malathion was applied was reported. Aim of the study was to extend knowledge on malathion toxicity on cellular and organ level and to evaluate embryotoxicity and genotoxicity for birds using the chick embryo model HET-CAM. METHODS: Skin and eye irritation was determined using reconstructed skin and eye cornea tissues and the chorioallantoic membrane of chick embryo to simulate conjunctiva. Cytotoxicity in 3T3 Balb/c fibroblast culture was determined to estimate acute systemic toxicity. Chick embryo model was further employed to evaluate acute embryotoxicity for birds (mortality and genotoxicity). Data were analysed by means of general linear models. RESULTS: Malathion is not a skin and eye irritant. Cytotoxicity in vitro test provided LD50 value of 616 mg/kg suggesting higher toxic potential than is generally published based on in vivo tests on laboratory rodents. Embryotoxicity studies revealed dose and age dependent mortality of chick embryos. Genotoxicity was identified by means of micronucleus test in erythroid cells isolated from chorioallantois vascular system of chick embryos. CONCLUSIONS: Using in vitro alternative toxicological methods, a higher toxic potential of malathion was demonstrated than is generally declared. An increased health and environmental hazard may occur in areas with intensive agricultural production. The environmental consequences of delayed effects and embryotoxicity for bird populations in areas exposed to organophosphate insecticides, such as malathion, are obvious.

• MeSH
• biologické modely MeSH
• buňky BALB 3T3 cytologie   účinky léků   MeSH
• chorioalantoická membrána cytologie   účinky léků   MeSH
• dráždivé látky toxicita   MeSH
• druhová specificita MeSH
• embryo nesavčí cytologie   účinky léků   MeSH
• insekticidy toxicita   MeSH
• kur domácí MeSH
• kuřecí embryo MeSH
• lineární modely MeSH
• malathion toxicita   MeSH
• mitóza účinky léků   MeSH
• myši MeSH
• rohovka cytologie   účinky léků   MeSH
• techniky in vitro MeSH
• testy akutní toxicity MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• kuřecí embryo MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dráždivé látky MeSH
• insekticidy MeSH
• malathion MeSH

The C. elegans genome encodes an unexpectedly large number of NHRs, the majority of which are classified as supplementary nuclear receptors (supnrs) that are likely to have evolved from an ancestral protein related to vertebrate HNF-4. To understand the need for this large repertoire of potential ligand-activated transcription factors, we have begun to study an 18-member subgroup defined by DNA binding domain relatedness. Here we report on NHR-60, a supnr expressed ubiquitously throughout development with a distinct pattern of localization on the nuclear periphery. Both antibody staining and GFP reporter genes demonstrated high-level expression and accumulation of NHR-60 in seam cell nuclei that is dependent on NHR-23 activity. Interference with NHR-60 activity, by either RNAi or overexpression of a putative dominant negative isoform, results in embryonic and early larval lethality, including defects in seam cell development. This adds NHR-60 to the list of C. elegans NHRs playing important roles in development.

• MeSH
• buněčné jádro metabolismus   MeSH
• Caenorhabditis elegans embryologie   genetika   růst a vývoj   metabolismus   MeSH
• dominantní geny MeSH
• embryo nesavčí cytologie   embryologie   metabolismus   MeSH
• embryonální vývoj MeSH
• genom u helmintů genetika   MeSH
• larva metabolismus   MeSH
• protein - isoformy genetika   metabolismus   MeSH
• proteiny Caenorhabditis elegans genetika   metabolismus   MeSH
• receptory cytoplazmatické a nukleární genetika   metabolismus   MeSH
• rekombinantní fúzní proteiny metabolismus   MeSH
• reportérové geny MeSH
• RNA interference MeSH
• specificita protilátek MeSH
• vývojová regulace genové exprese MeSH
• zelené fluorescenční proteiny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Intramural MeSH
• Názvy látek
• NHR-60 protein, C elegans MeSH Prohlížeč
• protein - isoformy MeSH
• proteiny Caenorhabditis elegans MeSH
• receptory cytoplazmatické a nukleární MeSH
• rekombinantní fúzní proteiny MeSH
• zelené fluorescenční proteiny MeSH