pinecone/core-2020-05-10-deduplication huggingface dataset:
A Candidate Gene for theamnionlessGastrulation Stage Mouse Mutation Encodes a TRAF-Related Protein

AbstractWe report the identification of a new recessive prenatal lethal insertional mutation,amnionless(amn).amnmutant embryos first appear abnormal during the Early Streak stage, between E6.5 and E7.0, when they initiate mesoderm production. Subsequently, theamnmutants become developmentally arrested between the Mid and Late Streak stages of gastrulation and they die and are resorbed between E9.5 and E10.5. While extraembryonic structures, including the chorion, yolk sac blood islands, and allantois appear to develop normally, the small embryonic ectoderm remains undifferentiated and generates no amnion. In addition, the embryonic mesoderm that is produced does not become organized into node, notochord, and somites and there is no morphological evidence of neural induction. Interspecific backcross and fluorescencein situhybridization analyses map the transgene insertion, and thus theamnmutation, to the distal region of mouse chromosome 12, which has synteny with human chromosome 14q32. A gene encoding a 7.5-kb transcript has been identified at a junction between the integrated transgene and host chromosome 12 sequences that meets three criteria expected of a candidateamngene. This gene maps to the site of transgene insertion; it is transcribed during gastrulation, and its expression is disrupted inamnmutant embryos. Nucleotide sequencing studies show that the 567 amino acid protein encoded by the 7.5-kb transcript is a member of the newly defined family of putative signal transducing proteins, TRAFs, that associate with the cytoplasmic domains of members of the tumor necrosis factor (TNF) receptor superfamily. Thus, we have named the gene encoding the 7.5-kb transcriptTRAFamn.TRAFamn is identical to a recently reported protein (CD40bp, CAP-1, CRAF1, LAP1) that can bind the cytoplasmic domains of CD40 and the lymphotoxin β receptor (LTβR), both of which are known members of the TNF receptor superfamily. The implications of these findings regarding a possible role for the TNF receptor superfamily during gastrulation are discussed
IGF-I and Insulin in the Acquisition of Limb-Forming Ability by the Embryonic Lateral Plate

AbstractAcquisition of limb-forming ability by discrete regions of the lateral plate of the chick embryo is dependent on a medial–lateral inductive signaling cascade moving sequentially from the area of Hensen's node to the somitic mesoderm, the intermediate mesoderm, and then to the prospective limb-forming regions of the lateral plate. IGF-I and insulin are expressed by medial tissues as they are influencing the prospective limb-forming regions of the lateral plate. Here we report that IGF-I and insulin, but not FGF-2 or FGF-4, induce the formation of limb bud-like structuresin vitrofrom prospective limb regions before they have acquired the ability to form limbs independent of medial tissues, and also induce the formation of limb bud-like structures from the prospective flank. The limb bud-like structures induced by IGF-I and insulin possess a thickened cap of ectoderm along their distal tips that resembles the apical ectodermal ridge (AER) and this thickened distal apical ectoderm expresses the AER-characteristic homeobox-containing geneMsx-2.Like in normal limb buds, a population of highly proliferating cells which express the homeobox-containing geneMsx-1are localized in the mesoderm directly subjacent to the thickened AER-like structures induced by IGF-I and insulin. However, the limb bud-like structures induced by IGF-I and insulin do not expresssonic hedgehog,which encodes a secreted signaling molecule that has been implicated in regulating the anteroposterior patterning of the developing limb bud. IGF-I- and insulin-treated prospective limb explants give rise to rudimentary limbs containing identifiable skeletal elements when grafted into the coelom or to somites of host embryos. Overall, these results suggest that IGF-I and insulin may be endogenous signals produced by medial tissues that are involved in conferring limb-forming ability to the lateral plate and may promote the initial outgrowth of limb buds and possibly induce the AER. However, other signals are necessary to promote the expression of genes such assonic hedgehogthat regulate the patterning of the developing limb
Increased Expression of αqFamily G-proteins during Oocyte Maturation and Early Development ofXenopus laevis

AbstractG-proteins of the αqfamily link extracellular stimulation of plasma membrane receptors to phospholipase C and consequently to intracellular Ca2+release. Because they might function in initiating Ca2+release at fertilization, we examined Gαqfamily proteins in oocytes and eggs ofXenopus laevis.Three members of this protein family were identified by immunoblotting and antisense depletion. These proteins are barely detectable in the immature oocyte, but undergo a 6-fold increase in amount during oocyte maturation. This increase in Gαqfamily protein expression correlates with the acquisition, during oocyte maturation, of the ability to release Ca2+at fertilization (Schlichter and Elinson, 1981,Dev. Biol.83, 33–41). In contrast, amounts of Gαsand Gαi3are constant during maturation. We also examined the amounts of Gαq, Gαs, and Gαi3proteins during early development. While amounts of Gαsand Gαi3show little or no change, Gαqfamily protein expression increases 27-fold between the egg and neurula stages, suggesting that these proteins may be important in initiating Ca2+release during early development
GATA-6: A Zinc Finger Transcription Factor That Is Expressed in Multiple Cell Lineages Derived from Lateral Mesoderm

AbstractMembers of the GATA family of zinc finger transcription factors play important roles in the development of several mesodermally derived cell lineages. In the studies described in this report, we have isolated and functionally characterized the murine GATA-6 cDNA and protein and defined the temporal and spatial patterns of GATA-6 gene expression during mammalian development. The GATA-6 and -4 proteins share high-level amino acid sequence identity over a proline-rich region at the amino terminus of the protein that is not conserved in other GATA family members. GATA-6 binds to a functionally important nuclear protein binding site within the cardiac-specific cardiac troponin C (cTnC) transcriptional enhancer. Moreover, the cTnC promoter enhancer can be transactivated by overexpression of GATA-6 in noncardiac muscle cells. During early murine embryonic development, the patterns of GATA-6 and -4 gene expression are similar, with expression of GATA-6 restricted to the precardiac mesoderm, the embryonic heart tube, and the primitive gut. However, coincident with the onset of vasculogenesis and development of the respiratory and urogenital tracts, only the GATA-6 gene is expressed in arterial smooth muscle cells, the developing bronchi, and the urogenital ridge and bladder. These data are consistent with a model in which GATA-6 functions in concert with GATA-4 to direct tissue-specific gene expression during formation of the mammalian heart and gastrointestinal tract, but performs a unique function in programming lineage-restricted gene expression in the arterial system, the bladder, and the embryonic lung
The Dynamics of Head Activation Changes during Proportioning inHydra oligactiswith Altered Head–Body Ratios

AbstractNormal hydra head–body proportions were altered by axially grafting a second head in place of the lower body column. The resulting animals had double the head tissue and one-quarter the normal body column. Changes in the head activation potential of tissue subjacent to both heads were monitored by assaying the ability of these animals to regenerate heads. The host head, the grafted head, or both heads were removed at varying times following graft construction and the animals were scored for head regeneration and/or the ability to express a head-specific antigen recognized by monoclonal antibody, CP8. In the presence of the grafted head, tissue subjacent to the host head lost the ability to regenerate a head or express the head-specific antigen over a 48-hr period. In the presence of the host head, tissue subjacent to the grafted head regenerated heads at a very low frequency and lost the ability to express the head-specific antigen over the same 48-hr period. Following simultaneous removal of both heads, animals initially regenerated both heads for the first 48 hr after graft construction. Then, both head regeneration and expression of the head-specific antigen declined gradually over the next 3 days, though not to the very low levels observed when one head remained. These data, especially the loss of CP8 labeling, support the hypothesis that loss of regeneration ability was due to a loss of head activation potential in tissues subjacent to the heads. We propose that this reflected the attempt of grafted animals to compensate for the altered head–body proportions through reproportioning. In keeping with this hypothesis, feeding the grafted animals to stimulate growth of body column tissue and a shift toward more normal head–body proportions prior to decapitation resulted in animals which were capable of regenerating heads when decapitated. Several interpretations of the results based on the Gierer–Meinhardt reaction-diffusion model of pattern formation are discussed
Induction of Embryonic Vasculogenesis by bFGF and LIFin Vitroandin Vivo

AbstractThede novoformation of blood vessels (vasculogenesis) is an integral part of embryogenesis. Elucidation of the role of cytokine cooperation in vasculogenesis may lead to a better understanding of organogenesis, blood vessel regulation during tumorigenesis, and tissue injury. We have used embryonic stem cells to derive an endothelial cell line, designated IEM, which expresses a range of endothelial markers, including Von Willibrand Factor VIII related antigen, vascular cell adhesion molecule, platelet-endothelial cell adhesion molecule (CD31), and receptors for acetylated low-density lipoprotein. More importantly, IEM cells can be induced upon exposure to combinations of basic fibroblast growth factor and leukemia inhibitory factor (LIF) to proliferate and undergo vasculogenesisin vitro,resulting in the formation of vascular tubes and microcapillary anastomoses. Moreover, exposure to both cytokines conditionally permits IEM cells to specifically chimerize microvascular endotheliumin vivofollowing blastocyst injection. These results indicate that bFGF and LIF together contribute to the induction and support of embryonic vasculogenesis in an isolated endothelial cell line. Our results provide evidence that combined actions of bFGF/LIF may play a role in mechanisms controlling blood vessel development
Regulated Expression of Homeobox GenesMsx-1andMsx-2in Mouse Mammary Gland Development Suggests a Role in Hormone Action and Epithelial–Stromal Interactions

AbstractThe murine homeobox genesMsx-1andMsx-2are related to theDrosophila mshgene and are expressed in a variety of tissues during mouse embryogenesis. We now report the developmentally regulated expression ofMsx-1andMsx-2in the mouse mammary gland and show that their expression patterns point toward significant functional roles.Msx-1andMsx-2transcripts were present in glands of virgin mice and in glands of mice in early pregnancy, but transcripts decreased dramatically during late pregnancy. Low levels ofMsx-1transcripts were detected in glands from lactating animals and during the first days of involution, whereasMsx-2expression was not detected during lactation or early involution. Expression of both genes increased gradually as involution progressed.Msx-2but notMsx-1expression was decreased following ovariectomy or following exposure to anti-estrogen implanted directly into the gland. Hormonal regulation ofMsx-2expression was confirmed when transcripts returned to normal levels after estrogen was administered to ovariectomized animals.In situmolecular hybridization forMsx-1showed transcripts localized to the mammary epithelium, whereasMsx-2expression was confined to the periductal stroma. Mammary stroma from which mammary epithelium had been removed did not transcribe detectable amounts ofMsx-2,showing that expression is regulated by contiguous mammary epithelium, and indicating a role for these homeobox genes in mesenchymal–epithelial interactions during mammary development
A Novel Sea Urchin Nuclear Receptor Encoded by Alternatively Spliced Maternal RNAs

AbstractScreening of a genomic library from the sea urchinStrongylocentrotus purpuratuswith a human COUP-TF I cDNA probe revealed the presence of a novel gene member of the steroid–thyroid–retinoic acid receptor superfamily, which was named SpSHR2 (S. purpuratusSteroid Hormone Receptor 2). Sequence analysis of the isolated genomic clone revealed that the DNA binding domain of this orphan receptor is most homologous to the human TR2 receptor. Using this sea urchin genomic fragment as probe, aS. purpuratusembryonic cDNA library was screened and two distinct but homologous cDNA clones were isolated. The two cDNAs encode the same DNA binding domain as the SpSHR2 gene and carry an almost identical 3′-untranslated sequence. One of the clones, however, is missing an entire region of about 1100 nt which includes the putative ligand binding domain. Genomic DNA hybridization suggests that SpSHR2 is a single-copy gene in theS. purpuratusgenome. Exon skipping during splicing of a single primary transcript appears to be the reason for the differently sized mRNAs. RNA blot hybridization results suggest that SpSHR2 transcripts are stored as maternal RNA in the egg and are not detected beyond the blastula stage.In vitrotranscription and translation of the full-length cDNA produced a polypeptide which specifically binds to the hormone response element in the 5′-flanking region of the sea urchin actin CyIIIb gene.In vivolabeling of proteins synthesized by cleavage stage embryos followed by immune precipitation of the SpSHR2 protein using specific antibodies reveals that the maternal SpSHR2 mRNA is being translated during early embryonic development
Pw1, a Novel Zinc Finger Gene Implicated in the Myogenic and Neuronal Lineages

AbstractThe cellular and molecular processes leading to the establishment of the skeletal muscle lineage in the vertebrate are not well understood. The MyoD-related family of myogenic regulatory factors (MRFs) are expressed during somitogenesis although cells with myogenic capacity are present prior to gastrulation. We propose that regulatory genes exist that guide the skeletal muscle lineage during early development. In an effort to identify these regulatory genes, we performed a differential screening to isolate transcripts that are present in myogenic cells and in the embryo prior to MRF expression but absent in nonmyogenic fibroblasts. We report here the identification of Pw1. The Pw1 transcript is ∼8.5 kb long and encodes a large protein containing 12 widespread C2H2 zinc fingers and 3 motifs containing periodic prolines and acidic residues. Consistent with the possibility that Pw1 is a transcription factor, we observe nuclear localization of the protein. Pw1 is strongly expressed upon gastrulation and subsequently becomes restricted to skeletal muscle and subregions of the central nervous system. Pw1 is initially expressed in all mesodermal cells early in development; however, its maintained expression in adult differentiated muscle suggests a specific role in the skeletal muscle lineage. Pw1 expression is cell cycle specific with levels highest during late M-phase. The gene is intronless which may facilitate transcription during cell division. At present, the precise function of Pw1 is not understood; however, we note that Pw1 maps to the proximal region of chromosome 7 near the axial segmentation mutantpudgywhich shows severe perturbation of axial skeletal and muscle structures
The Expression Pattern of the Mouse Receptor Tyrosine Kinase GeneMDK1Is Conserved through Evolution and RequiresHoxa-2for Rhombomere-Specific Expression in Mouse Embryos

AbstractSegmentation of the hindbrain has been conserved throughout the vertebrate species and results in the transient formation of rhombomeres, which are lineage-restricted compartments. Studies on the molecular mechanisms underlying the segmentation process have revealed that rhombomeric boundaries coincide with the expression limits of several evolutionary conserved genes such as the zinc-finger transcription factorKrox-20and homeobox genes which are expressed in a specific spatial and temporal order and have been shown to be important regulators of segmental identity. In addition toKrox-20and Hox genes, several members of the Eph subfamily of receptor protein tyrosine kinase (RTK) genes are also expressed in a segment-restricted manner in the hindbrain, suggesting that these receptors may act in concert with Hox genes to establish regional identity. In the cascade of regulatory interactions leading to segmental identity,Krox-20appears to act “upstream” of Hox genes, but the identity of the “downstream” effectors has not yet been identified. We report here the isolation of the zebrafish orthologue of the mouse RTK geneMDK1which belongs to the Eph receptor subfamily and show that the major expression domains of the mouse and the zebrafish genes have been conserved through evolution. Since the coincident spatial and temporal expression ofHoxa-2andMDK1in the mouse hindbrain suggested a possible regulatory link between them, we analyzed the expression of theMDK1inHoxa-2null mutant embryos. A selective lack ofMDK1expression in rhombomere 3 ofHoxa-2mutant hindbrains together with an overall altered expression pattern in the other rhombomeres was observed, thus demonstrating thatMDK1lies downstream ofHoxa-2in the morphogenetic signaling cascade
Analysis of Optical Density Wave Propagation and Cell Movement during Mound Formation inDictyostelium discoideum

AbstractAggregation fields ofDictyosteliumamoebae are organized by propagating concentric or spiral waves of cAMP. These waves coordinate cell movement directed toward the aggregation center. We now systematically investigated dark-field wave propagation and chemotactic cell movement during late aggregation and mound formation. The period and the signal propagation velocity decreased continuously during aggregation leading to a 15-fold decrease of the chemical wavelength. By analyzing the behavior of single GFP-labeled cells in aggregates and mounds we measured cell movement velocity, changes in cell shape, periodicity of cell movement, and cell trajectories. In early mounds of strain AX-3 dark-field waves propagated frequently as multiarmed (high-frequency) spirals. During the high-frequency waves observed in the early mound stage, cell movement speed is low and cell movement rather undirected. During tip formation the wave period decreased again and the cells started to rotate in the mound at unusually high average speeds of 40 μm/min. The rotation was almost monotonic with no clear periodicity. Since at this time the majority of the cells had already differentiated into prespore cells, this implies that prespore cells moved faster than aggregation stage cells. At 12 hr of development cell movement velocity dropped again and became highly periodic. These measurements show that the relay system is characterized by a specific temporal evolution, which is closely correlated with cellular differentiation. The remarkable changes in cell movement speed and period indicate a qualitative change in signal and movement parameters which might well be caused by the observed switch from high- to low-affinity cAMP receptors during mound formation. This switch might be required to copy with the increase in cell density and most likely plays a crucial role in the process of cell sorting
Stepwise Transfer from High to Low Lithium Concentrations Increases the Head-Forming Potential inHydra vulgarisand Possibly Activates the PI Cycle

AbstractLithium ions affect pattern formation in the freshwater polypHydra vulgarisin a complex manner. Although a long-term treatment with 1 mMLiCl completely suppresses both head formation and budding, a reduction of the lithium concentration during a long-term treatment from 4 to 1 mMLiCl strongly promotes the differentiation of ectopic head structures. Meanwhile, budding, often interpreted as a special case of head formation, remains suppressed. The appearance of ectopic tentacles under these conditions is surprising as they develop while the animals remain in the presence of 1 mMLiCl, a concentration which would normally suppress the formation of tentacles. On a molecular level, the induction of ectopic head structures by the shift in the LiCl concentration is preceded by an increase in the level of inositol phosphates, indicating an activation of the phosphatidylinositol (PI) cycle. Increased inositol phosphate levels persist for at least 24 hr. Our results provide evidence that (i) tentacle- and bud-forming systems need different and possibly mutually exclusive physiological preconditions and (ii) prolonged inhibition of the PI cycle after initial activation might be necessary to obtain ectopic tentacles
Expression of Zebrafishconnexin43.4in the Notochord and Tail Bud of Wild-Type and Mutantno tailEmbryos

AbstractCommunication via gap junctions provides a mechanism for the cell–cell transfer and coordination of developmental signals. The spatial restriction of gap junctions may also serve to organize cells into domains of coordinated behavior. To investigate the role of gap junctions during embryogenesis, we have characterized the expression of a member of the gap junction gene family, zebrafishconnexin43.4,a homolog ofconnexin45in chicken and mammals. Expression ofconnexin43.4was induced in the early gastrula, coincident with the first definitive assignments of axial cell fate and the onset of the cell movements comprising convergence and extension in zebrafish.In situhybridization and immunohistochemistry revealed that during gastrulationconnexin43.4mRNA and protein were progressively enriched in the germ ring and in the notochord primordia on the dorsal side of the embryo. Later in developmentconnexin43.4expression was detected in the notochord, the paraxial mesoderm, and the tail bud but was not observed after the differentiation of these tissues. Inno tailmutant embryos which are defective in tail formation and proper morphogenesis of the notochord,connexin43.4expression was absent during gastrulation from the caudal embryonic shield and notochord primordia. During somite stages inno tailembryos,connexin43.4expression remained absent in the notochordal precursor cells and was lost in the tail bud. Thus, theno tailgene product, a transcription factor, was required for the expression ofconnexin43.4in both the notochord and tail bud during morphogenesis. By microinjection of mRNA coding for a connexin43.4/green fluorescent protein fusion in the 1-cell zebrafish embryo, we showed that connexin43.4 is capable of assembling into structures reminiscent of gap junctions. The progressively restricted, developmental expression of the zebrafishconnexin43.4gene suggests that this gap junctional protein participates in the coordination of gastrulation and the formation of the notochord and tail