pinecone/core-2020-05-10-deduplication huggingface dataset:
CNTF and LIF Are Not Required for the Target-Directed Acquisition of Cholinergic and Peptidergic Properties by Sympathetic Neuronsin Vivo

AbstractDuring development, the sympathetic innervation of two targets, sweat glands and periosteum, changes the neurotransmitters it expresses from noradrenaline to acetylcholine and vasoactive intestinal peptide (VIP). The target-derived molecules that induce these changes have not been identified. Neuropoietic cytokines, including ciliary neurotrophic factor (CNTF) and leukemia inhibitory factor (LIF), induce the same phenotypic changes in sympathetic neuronsin vitroas sweat glands and periosteum doin vivo,raising the possibility that one of these factors mediates induction of cholinergic traits and VIP by these target tissues. Because CNTF and LIF have overlapping functions and signalling pathways, they could act interchangeably or in concert to influence neurotransmitter expression. To determine whether CNTF or CNTF and LIF together are responsible for the induction of cholinergic and peptidergic functionin vivo,we analyzed the neurotransmitter properties of sweat gland innervation in mice lacking CNTF or CNTF and LIF. We find that, as in wild-type mice, gland innervation in mice lacking one or both molecules appropriately expresses cholinergic properties and VIP immunoreactivity. Furthermore, footpads of mice lacking one or both genes contain choline acetyltransferase activity comparable to that of wild-type mice, and CNTF- or CNTF/LIF-deficient mice possess the normal complement of active sweat glands. We analyzed the innervation of a second, recently identified cholinergic sympathetic target, the periosteum, which is the connective tissue surrounding bone. Periosteal innervation of mice lacking CNTF, LIF, or both, like that of wild-type mice, is immunoreactive for the vesicular acetylcholine transporter, a recently identified cholinergic marker, and VIP. These results provide evidence that neither CNTF, LIF, nor a combination of the two are required for the developmental change from noradrenergic to cholinergic function that occurs in sympathetic innervation of sweat glands and periosteum
Successive Alteration and Recovery of Epidermal Differentiation and Morphogenesis after Specific UVB-Damages in Skin Reconstructedin Vitro

AbstractThe sequence of events affecting skin morphogenesis occurring after a single exposure to UVB was investigated on a model of human skin reconstructedin vitro.The biologically efficient dose (BED) able to induce the early UVB-DNA damages such as pyrimidine dimers, sunburn cells, and apoptotic keratinocytes was determined as 50 mJ/cm2. The subsequent changes induced during a period of 14 days following irradiation were analyzed. Up to Day 3, an epidermal disorganization led to a parakeratotic epidermis characterized by nucleated horny layers, as well as the down regulation of major markers of keratinocyte differentiation such as keratin 10, loricrin, filaggrin, and the keratinocyte transglutaminase (type I). On the contrary, the expression of involucrin and spr1 seemed to be unaffected, indicating distinct responses to UVB of proteins involved in keratinocyte differentiation. A progressive regeneration of normal epidermal morphogenesis begins from Day 4 leading to the normalization of keratinocyte differentiation at Day 10 to 14. In parallel, epidermal proliferation was increased. Taken together, these findings show that in skin reconstructedin vitro,UVB exposure leads to major epidermal developmental changes characterized by (i) an early apoptotic process, (ii) a subsequent down-regulation of specific keratinocyte differentiation markers, and (iii) the recovery of both the early and delayed effects resulting in normal epidermal morphogenesis
Regulation of Transcriptional Activity during the First and Second Cell Cycles in the Preimplantation Mouse Embryo

AbstractTranscription of endogenous genes in preimplantation 1- and 2-cell mouse embryos was determined by monitoring the incorporation of BrUTP by plasma membrane-permeabilized embryos. Incorporation is observed starting by mid-S phase in the 1-cell embryo and increases progressively; the amount of incorporation by the 1-cell embryo in G2 is about 20% that of the 2-cell embryo in G2. Incorporation by the male pronucleus is always about four to five times greater than that of the female pronucleus. Nevertheless, the amount of incorporation by the female pronucleus present in parthogenetically activated eggs is similar to the total amount of incorporation in inseminated eggs, i.e., the transcriptional capacity of the female pronucleus is not inherently less than that of the male pronucleus. Inhibiting the first round of DNA replication does not prevent the initiation of transcription in the 1-cell embryo, but does inhibit the extent of BrUTP incorporation by 35%. The transcriptional machinery of the 1-cell embryo appears to be rate-limiting, since the total amount of BrUTP incorporation by parthenogenetically activated and dispermic eggs is similar to that in monospermic eggs; trispermic eggs incorporate BrUTP to only about 60% the level of monospermic eggs. A transcriptionally repressive state may start to develop in the 2-cell embryo, since inhibiting the second round of DNA replication results in an 50% increase in BrUTP incorporation. Trapoxin treatment, which induces histone hyperacetylation, enhances incorporation by 2-cell embryos 1.8-fold and suggests that histone hyperacetylation can relieve this repression
Steroid Hormones Act Directly to Trigger Segment-Specific Programmed Cell Death of Identified Motoneuronsin Vitro

AbstractIn larvae of the hawkmoth,Manduca sexta,accessory planta retractor (APR) motoneurons undergo a segment-specific pattern of programmed cell death at pupation. APR death is triggered hormonally by the prepupal peak of the ecdysteroid, 20-hydroxyecdysone (20-HE). Previous studies found no evidence that cellular interactions regulate the segmental pattern of APR deathin vivo.To test the hypothesis that 20-HE acts directly on APRs to trigger a cell-autonomous, segment-specific pattern of death, APRs were labeled with the fluorescent dyes DiI or DiA, removed from the nervous system before the prepupal peak, and placed in low-density cell culture. Physiological levels of 20-HE triggered the same segment-specific pattern of APR deathin vitroas seenin vivo,both in cultures containing a single APR and in cultures containing two APRs removed from the same donor animal. The presence or absence of contact with other cells did not influence the APRs’ responses to 20-HE. The death of APRs in culture was characterized by fragmentation or rounding up of the cell body and fragmentation of the neurites. These findings suggest that intrinsic segmental identity regulates whether these motoneurons live or die when exposed to a steroid hormone during development
Meiotic and Mitotic Ca2+Oscillations Affect Cell Composition in Resulting Blastocysts

AbstractAt fertilization periodic Ca2+oscillations release oocytes from meiotic arrest. The present study examined whether these oscillations have a long-term role in pre- and postimplantation development, independent of their immediate effect. Sr2+-containing medium was used to induce oscillations during exit from meiosis and first embryonic mitosis and Sr2+-activated parthenotes were compared to ethanol-activated parthenotes and embryos generated byin vitrofertilization. After embryo culture, blastocysts were differentially stained for the inner cell mass and trophectoderm. It was found that oscillations both during exit from meiosis and during mitosis acted to increase the number of inner cell mass cells. In contrast, the trophectoderm cell number was largest in ethanol-activated parthenotes and smallest in fertilized embryos. Postimplantation development was also modestly improved by extending the time of exposure to Sr2+-containing medium. Together these data suggest that Ca2+oscillations have a role in long-term embryonic events and that they provide more than merely a stimulus for meiotic resumption
Change in Intracellular Ca2+Is Not Involved in Serotonin-Induced Meiosis Reinitiation from the First Prophase in Oocytes of the Marine BivalveCrassostrea gigas

AbstractIn response to the neurohormone serotonin (5-hydroxytryptamine, 5-HT), prophase-arrested oocytes of the marine bivalveCrassostrea gigas(oyster) reinitiate meiosis, undergo germinal vesicle breakdown (GVBD), and are arrested again at metaphase I. We examined the pharmacological characteristics of 5-HT receptors and the signal transduction pathway following 5-HT stimulation in oyster oocytes. Among 5-HT agonists tested, only α-methyl 5-HT, a 5-HT2agonist, induced GVBD, although it was 1000 times less sensitive than 5-HT. The rank order of the potency of 5-HT antagonists to inhibit GVBD was propranolol, cyproheptadine > metoclopramide > mianserin. These results are quite different from those reported for other mollusks, suggesting the presence of unique 5-HT receptors on oyster oocytes. Using the fluorescent Ca2+dyes fura-2 and calcium green and the pH indicator 1-hydroxypyrene-3,6,8-trisulfonic acid, we examined changes in intracellular Ca2+([Ca2+]i) and intracellular pH (pHi) during 5-HT-induced meiosis reinitiation. 5-HT did not trigger any changes in [Ca2+]i. However, an increase in pHiwas observed during the 5-HT-induced meiosis reinitiation. The increased pHilevel was rather small before GVBD and not necessary for GVBD, because lowering pHiby sodium acetate seawater (pH 7.0) did not prevent 5-HT-induced GVBD. Measurement of the kinase activity toward a peptide substrate specific to cdc2 demonstrated that maturation-promoting factor (MPF) was activated in accordance with the occurrence of GVBD in response to 5-HT. Therefore, it is likely that in oyster oocytes the signal transduction pathways and intracellular effectors participating in 5-HT-induced meiosis reinitiation via the activation of MPF are insensitive to [Ca2+]iand pHi
Caenorhabditis elegansHOM-C Genes Regulate the Response of Vulval Precursor Cells to Inductive Signal

AbstractFactors that determine the competence of cells to respond to extracellular cues are not well understood. We demonstrate that two HOM-C transcription factors have antagonistic roles in determining the ability ofCaenorhabditis elegansvulval precursor cells (VPCs) to respond to the inductive signal from the anchor cell of the somatic gonad. The vulva develops from a subset of ectodermal vulval precursor cells distributed along the anteroposterior axis. Vulval patterning depends on both a localized inductive signal, the LIN-3 growth factor, and lateral signaling between induced VPCs. One HOM-C gene, theAntphomologmab-5,is expressed in the posterior two VPCs. By examining the response of single VPCs to controlled doses of inductive signal in wild-type and inmab-5mutant animals, we demonstrate thatmab-5reduces the competence of these two cells. Moreover, a gain-of-function allele ofmab-5that causes ectopic expression of MAB-5 in all VPCs reduces the sensitivity of all VPCs to inductive signal. Additional experiments suggest that another HOM-C gene, theScrhomologlin-39,is required for VPCs in wild-type animals to respond to activation of inductive signal. Genetic epistasis tests are consistent with models in whichlin-39acts downstream of the RAS pathway to regulate response to inductive signal. We propose that the spatial pattern of HOM-C gene expression may enhance the precision of vulval fate patterning
The PIT-1 Gene Is Regulated by Distinct Early and Late Pituitary-Specific Enhancers

AbstractThe differentiation of three anterior pituitary cell types is regulated by the tissue-specific POU domain factor Pit-1, which is initially expressed on Embryonic Day 13.5–14 in mice. ThePit-1gene remains continuously, highly expressed in the somatotrope, thyrotrope, and lactotrope cells of the adult. Using the Pit-1-defective Snell dwarf as a genetic background, we demonstrate that thePit-1gene utilizes distinct enhancers for initial gene activation and for subsequent autoregulation (required for maintenance of expression) and that Pit-1-dependent activation of the distal enhancer can be mediated in the absence of the early enhancer. These two distinct enhancers provide the basis for temporally specific regulation by discrete pituitary-specific factors, events likely to be prototypic for regulation of other classes of genes encoding transcription factors controlling terminal differentiation
Genetic Enhancers ofsem-5Define Components of the Gonad-Independent Guidance Mechanism Controlling Sex Myoblast Migration inCaenorhabditis elegansHermaphrodites

AbstractThe migrations of the sex myoblasts inCaenorhabditis eleganshermaphrodites involve two guidance mechanisms: a gonad-dependent attraction that confers precise positioning of the sex myoblasts and a gonad-independent mechanism that is sufficient for coarse positioning in the absence of the gonad (Thomaset al.,1990). Here we show that mutations inunc-53, unc-71,andunc-73disrupt sex myoblast positioning in the absence of the gonad, while they do not affect positioning in the presence of the gonad. Thus, mutations in these genes appear to compromise the gonad-independent mechanism without affecting motility or the gonad-dependent attraction. Mutations insem-5confer dramatic sex myoblast positioning defects in double mutant combinations withunc-53, unc-71,orunc-73mutations, even in the presence of the gonad. This suggests thatsem-5is required for the gonad-dependent attractive mechanism. Mutations inlet-60 rasandlet-341also confer sex myoblast migration defects in anunc-53background, implicating these genes in gonad-dependent positioning as well
Retinoic Acid Directs Cardiac Laterality and the Expression of Early Markers of Precardiac Asymmetry

AbstractFormation of the left/right body axis is a critical early step in embryogenesis. The heart loop is one of the first clearly recognizable morphological asymmetries, and the molecular pathway which dictates this laterality is now beginning to be understood. We report here that the left and right precardiac fields of chick differ in their sensitivity to retinoic acid (RA); while RA applied to the right precardiac field at gastrulation randomizes heart looping, left side treatment induces situs inversus only at high RA concentrations. We identified two extracellular matrix proteins, the heart-specific lectin-associated matrix protein-1 (hLAMP1) and the fibrillin-related protein recognized by the antibody JB3, which are distributed asymmetrically within the precardiac fields at the head process stage. In normal embryos, JB3 expression is enhanced within the right precardiac field, and hLAMP-1 is enriched within the left. RA treatment predictably altered the expression of these proteins in a manner consistent with subsequent heart laterality: RA treatments which randomize heart loop direction also equalized or reversed the left/right JB3 and hLAMP-1 distribution prior to heart tube fusion. The existence of asymmetrically expressed extracellular matrix proteins within precardiac regions suggests that interactions between cardiocytes and their environment may contribute to heart laterality determination and looping
Control of Early Neurogenesis of theDrosophilaBrain by the Head Gap Genestll, otd, ems,andbtd

AbstractThe progenitors of theDrosophilacentral nervous system (CNS), called neuroblasts, segregate from the neurectoderm of the early embryo in a stereotyped pattern. The neuroblasts that give rise to the brain segregate from the procephalic neurectoderm and form three neuromeres, called protocerebrum, deuterocerebrum, and tritocerebrum. The expression of the proneural genes of theachaete-scutecomplex (AS-C) is required for neurectodermal cells to acquire the competency to form neuroblasts. We show here that the expression of the proneural genelethal of scute(l'sc) is required for the development of the majority of the procephalic neuroblasts.l'scexpression in the procephalic neurectoderm is controlled by the head gap genestailless(tll),orthodenticle(otd),buttonhead(btd), andempty spiracles(ems), which are expressed in partially overlapping domains of the head neurectoderm. Loss of function of a given head gap gene results in the absence ofl'scexpression in its domain, followed by the absence of neuroblasts that would normally segregate from this domain. Loss oftllfunction results in the absence of all protocerebral neuroblasts.otdfunctions in a domain that includes a large part of the protocerebrum and a smaller part of the adjacent deuterocerebrum. Bothemsandbtdare required in partially overlapping subsets of neuroblasts of the deuterocerebrum and tritocerebrum
Induction of Additional Limb at the Dorsal–Ventral Boundary of a Chick Embryo

AbstractIn the early chick embryo, an apical ectodermal ridge (AER) is formed from the overlying ectoderm of the presumptive limb bud region at the dorsal–ventral (DV) boundary. We report here that the ectopic DV boundary formed in the presumptive wing, flank, and leg fields induces an ectopic AER structure. Dorsal tissue (ectoderm and mesoderm) from the presumptive wing field of stage 10 to 17 embryos was inserted into a slit in the somatopleure of the future ventral side of host embryos. The same method was used to implant ventral tissue into the future dorsal side of host embryos. After the implantation, ectopic AER was induced and an additional limb or limb-like structure developed. In related experiments, ectoderm-free presumptive wing tissue was implanted, which resulted in a considerably decreased frequency of ectopic AER formation. Further analysis of chick and quail chimeras suggests that the ectopic AER was formed from the ectodermal cells overlying the boundary of host and graft mesodermal cells. These results indicate that the DV boundary organizes the AER structure in the limb bud field of early-stage chick embryos and that the ectoderm of the grafted tissues plays an important role in this process
A Set of Novel Tadpole Specific Genes Expressed Only in the Epidermis Are Down-Regulated by Thyroid Hormone duringXenopus laevisMetamorphosis

AbstractFour genes were identified in a screen for thyroid hormone-induced down-regulation of gene expression inXenopus laevistadpole tails. All four encode extracellular glycoproteins that are expressed exclusively in the apical cell layer of the entire tadpole epidermis, which is the equivalent of the mammalian fetal periderm. The onset of the four novel genes’ expression late in embryogenesis, their activity throughout the life of the tadpole, their repression by exogenously added thyroid hormone, and the spontaneous cessation of their expression at the end of tadpole life are closely coordinated. These facts suggest that the protein products of these genes form a novel albeit temporary barrier or other structure in the tadpole epidermis that functions in lieu of the cornified, stratified epithelium of the adult epidermis. We have exploited the cloning of these genes for use as cell-specific markers to follow the appearance and loss of apical cells during development. We were able to demonstrate directly that the apical cells are derived from a stratification of the embryonic ectoderm at the onset of the formation of a true epidermis. The apical cells uniformly cover the surface of the tadpole until metamorphosis, when the expression of the four larval epidermis-specific genes is lost coordinately over the entire tadpole. In contrast, the adult epidermis develops with a distinct regional specificity: adult keratin is first expressed up to a line separating the body and tail epidermis and finally appears in the tail only at metamorphic climax. Finally, our analysis reveals that the TH-induced down-regulated gene expression program during metamorphosis is very different from the previously described up-regulated program which involves multiple cell types and several waves of gene expression changes. The down-regulated program only consists of the repression of a small number of genes which are expressed in larval cells preprogrammed to die during the larval to adult transition at metamorphosis
Developmental Expression of the Inositol 1,4,5-Trisphosphate Receptor and Structural Changes in the Endoplasmic Reticulum during Oogenesis and Meiotic Maturation ofXenopus laevis

AbstractTo study the development of the calcium release mechanism, we examined the temporal and spatial expression of inositol 1,4,5-trisphosphate receptor (IP3R) during the oogenesis and meiotic maturation ofXenopus laevis.Observation of a series of fixed samples by immunofluoresence microscopy revealed a relocalization ofXenopusIP3R (XIP3R)-positive structures during meiotic maturation. We visualized the endoplasmic reticulum (ER) using ER-sensitive dye, DiI, by observation under confocal laser scanning microscopy. Time-lapse visualization of the living oocytes revealed that while the ER of immature fully grown oocytes underwent relatively little movement, the ER of maturing oocytes and mature eggs moved rapidly. A possible role for the increase of ER mobility in the dynamic redistribution of XIP3R during oocyte maturation is also discussed
Neural Activity Affects Distribution of Glutamate Receptors during Neuromuscular Junction Formation inDrosophilaEmbryos

AbstractChanges in the distribution and density of transmitter receptors in the postsynaptic cell are required steps for functional synapse formation. We raised antibodies againstDrosophilaglutamate receptors (DGluR-II) and visualized the distribution of receptors during neuromuscular junction formation in embryos. In wild-type embryos, embryonic development is complete within 22 hr after egg lying (AEL) and neuromuscular junction (NMJ) formation begins at 13 hr AEL. At the time of initial synapse formation, DGluR-IIs appeared as clusters closely associated with some muscle nuclei. Subsequently, these nonjunctional clusters dispersed while DGluR-IIs accumulated at the junctional region. In a paralytic temperature-sensitive mutant,parats1,neural activity decreases drastically at restrictive temperatures. When neural activity was blocked throughout synaptogenesis by rearing embryos at a restrictive temperature prior to the beginning of synaptogenesis, 12 hr AEL, the dispersal of extrajunctional clusters was significantly suppressed and no accumulation of receptors at the junction was observed at 22 hr AEL. However, when neural activity was blocked later, by rearing embryos at a restrictive temperature from 13 hr AEL, DGluR-IIs did not accumulate at the NMJ, although extrajunctional clusters dispersed normally. These findings suggest that the neural activity differentially regulates dissipation of receptor clusters in the nonjunctional region and accumulation of receptors at the junctional region