pinecone/core-2020-05-10-deduplication huggingface dataset:
A Somatic Reproductive Organ Enhancer Complex Activates Expression in both the Developing and the MatureDrosophilaReproductive Tract

AbstractTheGlucose dehydrogenase(Gld) gene is highly expressed in the matureDrosophilareproductive tract. Unlike several otherDrosophilagenes which function in reproductive physiological processes,Gldis also expressed extensively in the developing reproductive tract during metamorphosis. Proximal promoter elements driveGldexpression in a variety of tissues throughout development, but not in the reproductive tract. Herein, we have identified a somatic reproductive organ enhancer complex (SREC) containing multiple redundant enhancer modules inGldintron I (+639 to +3906 nt). The SREC, in combination with theGldpromoter, activates βgalactosidase reporter gene expression in both the developing and the mature reproductive tract. The SREC activates a heterologoushsp70promoter in the ejaculatory duct, but not in other reproductive tract tissues, suggesting that the SREC acts synergistically withGldpromoter proximal elements. Through deletion analysis we have delimited a 361-nt region of the SREC that is involved in ejaculatory duct/oviduct-specific expression. The ejaculatory duct/oviduct enhancer retains the ability to activate expression in both the developing and the mature reproductive tract, suggesting that the same basic enhancer elements activateGldexpression during metamorphosis and in adults. A model of the evolution ofGldexpression in the ejaculatory duct and oviduct is presented
The Cyclic GMP-Mediated Calcium Release Pathway in Sea Urchin Eggs Is Not Required for the Rise in Calcium during Fertilization

AbstractThe mechanisms required for cGMP-induced Ca2+release in the sea urchin egg were investigated using both egg homogenates and intact eggs. The postulated pathway of cGMP-dependent protein kinase (PKG) activation of ADP-ribosyl cyclase for production of cADPR to activate the ryanodine receptor Ca2+channel was tested with a variety of activators (cGMP analogs and cIMP) and inhibitors (Rp-8-pCPT-cGMPS, 3-aminopyridine NAD, nicotinamide, and spermine). Our observations are consistent with Ca2+release by cGMP in the egg being dependent on an isoform of PKG that is distinct from the mammalian enzyme. PKG activity in the sea urchin egg was activated by cIMP, but was insensitive to cGMP analogs, which are potent activators of mammalian isoenzymes. Surprisingly, it appears the activation of the cGMP-dependent Ca2+release pathway was unnecessary during fertilization. Inhibitors of either PKG or ADP-ribosyl cyclase activities did not prevent the transient rise in intracellular Ca2+activity in heparin-loaded eggs during fertilization. These results suggest the synthesis of cADPR during fertilization is not necessary for regulating the Ca2+event
Transcriptional Analysis of the Candidate Spermatogenesis GeneUbe1yand of the Closely RelatedUbe1xShows That They Are Coexpressed in Spermatogonia and Spermatids but Are Repressed in Pachytene Spermatocytes

AbstractUbe1yis a Y-linked gene transcribed in the testis, which maps to a region of the mouse Y required for normal spermatogonial proliferation.Ube1y,together with a ubiquitously expressed homologue on the X chromosome (Ube1x), encodes ubiquitin-activating enzyme E1, an enzyme essential for eukaryotic cell proliferation.Ube1yis thus a strong candidate for the Y function in spermatogonial proliferation. Using probes specific for the two genes, we have used Northern analysis and RNase protection to assess transcript levels throughout testis development and, by using germ cell-deficient XXSxratestes and purified cell fractions, we have defined the testicular cell types in which transcription occurs.Ube1ytranscripts are already detectable in the fetal testis at 12.5 dpc, with higher levels at 14.5 dpc and then falling to low levels by the time of birth. Postnatally levels rise sharply, peaking at 10 dpp. Analysis of XXSxratestes indicates that the bulk of theUbe1ytranscription is in germ cells. The analysis of purified cell fractions shows that X- and Y-encoded transcripts are present in A spermatogonia, both are at very low levels (or perhaps absent) in pachytene spermatocytes and then return to high levels in round spermatids. The reactivation of transcription in round spermatids implies a requirement for the ubiquitination pathway at this time. The presence ofUbe1xtranscripts in A spermatogonia raises the question as to whyUbe1ytranscripts are required. This question is discussed in relation to the spermatogenic failure in XSxrbO mice which are deleted forUbe1yand it is argued thatUbe1yserves to increase UBE1 production at a time of high demand.Ube1ytranscripts were also detected in XXY and XY ovaries
Activation ofSiamoisby theWntPathway

AbstractTheWntpathway and the recently describedXenopushomeobox geneSiamoisshare the ability to mimic Nieuwkoop organizer signaling activity when ectopically expressed, prompting us to ask whether theWntpathway can activateSiamoisexpression. We show that activators of theWntpathway, and the dorsalizing substance LiCl, activateSiamoisexpression inXenopusanimal caps. Furthermore,Siamoisexpression is shown to be activated by β-catenin cell-autonomously. Although certain TGF-β family members, such as Vg1, are potent dorsal mesoderm inducers, the TGF-β pathway only weakly activatedSiamois.Finally, we demonstrate thatSiamoisexpression is eliminated from the marginal zone of UV-irradiatedXenopusembryos, supporting the hypothesis that cortical rotation moves aWnt-like activity into the dorsal region. These results suggest that formation of the Nieuwkoop organizer is dependent on activation ofSiamoisby a localizedWnt-like signaling activity, which may act synergistically with a vegetally localized TGF-β signal
A Gradient of Cactus Protein Degradation Establishes Dorsoventral Polarity in theDrosophilaEmbryo

AbstractDorsoventral polarity in theDrosophilaembryo is established by a signaling pathway active on the ventral and ventrolateral surfaces of the embryo. Signal transduction via the protein kinase Pelle frees the Rel-related protein Dorsal from its cytoplasmic inhibitor Cactus, allowing Dorsal to translocate into ventral and ventrolateral nuclei and direct gene expression. Here, we show by immunochemical analyses that Pelle-mediated signaling induces the spatially graded degradation of Cactus. Using a tissue culture system which reconstitutes Pelle-dependent Cactus degradation, we show that a motif in Cactus resembling the sites of signal-dependent phosphorylation in the vertebrate homologs IκB-α and IκB-β is essential for Pelle-induced Cactus degradation. Substitution of four serines within this motif with nonphosphorylatable alanine residues generated a mutant Cactus that still functions as a Dorsal inhibitor but is resistant to induced degradation. Injection of RNA encoding this altered form of Cactus has a dominant negative effect on establishment of dorsoventral polarity in the embryo. We conclude that dorsoventral signaling results in a Cactus concentration gradient and propose that signal-dependent phosphorylation directs the spatially regulated proteolysis of Cactus protein
Maternal Effects of theshort integumentMutation on Embryo Development inArabidopsis

AbstractMaternal gene products deposited in an animal egg determine the polarity of embryonic axes and regulate embryonic cell–cell communication important for morphogenesis. Here we report the first maternal-effect embryo-defective mutation discovered in a plant. Recessive mutations in theSHORT INTEGUMENT(SIN1) gene inArabidopsiswere previously shown to influence ovule development and flowering time. Here we show that asin1mutation has a pronounced maternal effect on zygotic embryo development. A homozygoussin1mutant embryo is normal when nursed by asin1/+ heterozygous maternal sporophyte. Strikingly, asin1or asin1/+ embryo that is nursed by asin1homozygous maternal sporophyte develops morphogenetic defects in the apical–basal and radial axes. The defects resemble those seen in some zygotic-effect embryonic pattern formation mutants. These results imply that in maternal cells theSIN1gene either codes for or controls the production of a diffusible morphogen necessary for proper zygotic embryogenesis
Jagged2: A Serrate-like Gene Expressed during Rat Embryogenesis

AbstractDSL (Delta,Serrate,Lag-2) ligands activate Notch signaling and thereby regulate the differentiation of many different cell types during development. We have isolated a novel Serrate-like gene,Jagged2,whose amino acid sequence and expression pattern during rat embryogenesis suggest that it functions as a ligand for Notch. In contrast to previously described DSL ligands for Notch, Jagged2 is not widely expressed in the developing central nervous system. However, Jagged2 and Notch1 are coexpressed in the apical ectodermal ridge (AER), suggesting a role for this ligand–receptor pair in limb development. Furthermore, unlike Jagged1, Jagged2 is coexpressed with Notch in the developing thymus, where it may induce Notch signaling to direct T-cell fate. Our data are consistent with the idea that the diversity of cell types regulated by Notch signaling is a consequence of activation of unique Notch isoforms by different DSL ligands
Adhesion in Development: An Historical Overview

AbstractMy purpose here is to provide brief historical overviews of three related subjects conceptually fundamental to the broader subject of “cell adhesion in development.” These subjects are (1) the evolution of our present understanding of how animal cells cohere; (2) the question of what principles underlie the ability of embryonic cell populations to organize themselves into anatomically correct structures; and (3) the ongoing effort to understand the origins of the “recognition specificity” evinced in the latter phenomenon. Because this review must be brief, it is not possible to mention all of the significant advances, many of which will be referenced in a recent more detailed review of this subject (Grunwald, 1991). For the same reason, the important work on cell adhesion in nonvertebrate systems is not included
Cadherins in the Developing Central Nervous System: An Adhesive Code for Segmental and Functional Subdivisions

AbstractIn this review, we describe general features of the expression of cadherins in the developing central nervous system (CNS) of vertebrates. In the early neuroepithelium, the expression of several cadherins is restricted to specific regions corresponding to segmental domains. Segmental boundaries often coincide with changes in cadherin expression, subdividing the primordial CNS into different adhesive domains. In the different neuromeric domains, early neurons are generated which differentially express cadherins. In the mantle layer, these early neurons seem to sort out according to which cadherin they express, and they aggregate into various gray matter regions (brain nuclei and cortical lamina and regions). The gray matter structures expressing a given cadherin become connected to one another to form parts of particular functional systems or neuronal circuits. Together, these findings show that cadherins provide a molecular system reflecting both early embryonic and mature nervous system architecture. The possible roles of cadherins in the formation and maintenance of segmental and functional nervous system structures are discussed
Neuronal Pathfinding and Recognition: Roles of Cell Adhesion Molecules

AbstractNeurons contact their neighbors through a diverse array of cell adhesion and other surface molecules. These molecules can exhibit highly regulated patterns of expression, underscoring their multiple roles in establishing specific interactions between neurons and their environment. Recent studies are beginning to ask how these membrane-bound neural recognition molecules interact with each other and intracellular signaling pathways within an individual neuronal growth cone, and direct the formation of neural connections during development
CnNK-2,an NK-2 Homeobox Gene, Has a Role in Patterning the Basal End of the Axis in Hydra

AbstractNK-2-class homeobox genes have been identified in a variety of metazoans, from sponges to arthropods and vertebrates, and have been shown to play roles in a variety of cell and tissue specifications. Here we describe the characterization of the NK-2 homologCnNK-2fromHydra vulgaris,a freshwater cnidarian.CnNK-2expression is restricted to the endodermal epithelial cells of hydra and is primarily in the peduncle, the lower end of the body column. In some species it is graded along the apical–basal axis with a maximum in the basal tissue of the lower peduncle, adjacent to the foot.CnNK-2expression invariably precedes foot formation as part of the normal tissue dynamics of the adult as well as during asexual reproduction by budding, foot regeneration, or ectopic foot formation. Manipulations which alter the gradient of positional value along this axis affectCnNK-2expression in a manner which indicates that expression of this gene is closely linked to the gradient. The normal and altered patterns of expression of this gene extend the understanding of the regulation of foot formation in hydra
Redistribution and Increase in Cortical Inositol 1,4,5-Trisphosphate Receptors after Meiotic Maturation of the Mouse Oocyte

AbstractMouse oocytes develop sensitivity to inositol 1,4,5-trisphosphate (IP3) during oocyte maturation. We recently reported that a change in the organization of the endoplasmic reticulum (ER) during oocyte maturation may contribute to this enhanced sensitivity (Mehlmannet al.,1995,Dev. Biol.170, 607–615). Here, we investigated whether there is an increase in the number of available IP3receptors after maturation and whether there is a redistribution of IP3receptors similar to the redistribution of the ER that occurs during maturation. Western blot analysis of the IP3receptor in oocytes and eggs demonstrated a 1.8-fold increase in immunoreactive mass of the IP3receptor following oocyte maturation. Microinjection of the function-blocking monoclonal antibody 18A10 inhibited IP3-induced Ca2+release in a concentration-dependent manner in both eggs and oocytes. More antibody was required to inhibit Ca2+release to the same extent in eggs compared to oocytes when both were injected with the same concentration of IP3, suggesting that eggs contain a greater number of functional IP3receptors. Immunolocalization of the IP3receptor revealed that receptors were present in large clusters, 1–2 μm in diameter, in the cortex of the mature egg except in a ring-shaped band of cortex adjacent to the meiotic spindle. In contrast, receptor clusters were located around the entire cortex of the immature oocyte and were much smaller (<1 μm); larger patches were sometimes seen, but they did not display the same spherical organization as those in eggs. These results suggest that the number of cortical IP3receptors increases during mouse oocyte maturation and that this increase may contribute to enhanced Ca2+release at fertilization
A Receptor Tyrosine Kinase, Sky, and Its Ligand Gas 6 Are Expressed in Gonads and Support Primordial Germ Cell Growth or Survival in Culture

AbstractAlthough a number of growth factors and their receptors are involved in the proliferation and differentiation of primordial germ cells (PGCs), the only factor that has been shown to be activein vivois Steel factor, a ligand for c-Kit. To identify new growth factor receptors that may be required for PGCs functionin vivo,we used an reverse transcription–polymerase chain reaction-based strategy to screen for protein kinase genes expressed in PGC-derived embryonic germ cells. We report here that one such gene encoding the receptor tyrosine kinase, Sky, is expressed in both PGCs and their supporting cells in male genital ridges after 11.5 dpc. Interestingly,Skyexpression was not detected in female genital ridges, although transcripts were detected in supporting cells in the developing ovary at later stages. Gas 6, a ligand for Sky, was also expressed in interstitial cells which surroundSkypositive cells in genital ridges, and, in addition, it supported PGC growth or survival in culture. After birth,Skyexpression in testis was restricted to Sertoli cells, and Gas 6 was detected around peritubular cells and Leydig cells. These results suggest that Gas 6–Sky signaling plays a role in PGC growth, sexual differentiation, and Sertoli cell functionsin vivo. Skyexpression in Sertoli cells diminished by 3 weeks of age, when haploid germ cells first appear. On the other hand, the expression in Sertoli cells was markedly upregulated in the testis of germ cell-deficientW/Wvandjsd/jsdmice. The results suggest that signals from differentiated germ cells suppressSkygene expression in Sertoli cells. High-resolution chromosomal mapping ofSkyis also reported
Positional Information and Whorl Morphogenesis inPolysphondylium

AbstractCellular slime molds of the genusPolysphondyliumperiodically release cell masses from the base of culminating fruiting bodies. These masses quickly undergo a change in symmetry from spherical to radial as they differentiate into distinctive arrays of secondary fruiting bodies arranged about a primary axis of stalk cells. Here we show that a major event in whorl morphogenesis is the activation of a prestalk-specific promoter early and globally in newly forming whorls. With time, transcript synthesis and amplification become restricted to the equator of the whorl and then to patches which define where secondary tip morphogenesis will occur. The localization of early prestalk message synthesis depends on positional information, in contrast to the establishment of early prestalk/prespore patterns in bothPolysphondyliumandDictyostelium
Differential Activation of the Clustered Homeobox GenesCNOT2andCNOT1during Notogenesis in the Chick

AbstractCNOT2,a newly identified homeobox gene, is physically linked to theCNOT1gene in the chicken genome. The two chicken genes represent two different subgroups of theNotgene family, the first includingCNOT1and theXenopusgenesXNot1andXNot2,and the secondCNOT2and the zebrafishfloating headgene. The overall expression pattern ofCNOT2in Hensen's node, notochord, neural plate, tailbud, and epiphysis resembled theCNOT1pattern. However, several significant differences occurred:CNOT2expression was much stronger and more widespread in the pregastrulation embryo, it showed an additional, transient domain on the anterior intestinal portal, and lacked expression on the early anterior neural folds and the anterodistal limb bud. We studied CNOT expression by transplanting parts of the primitive streak into growing embryos or by explanting them into tissue culture.CNOTgene expression from young nodes was maintainedin vivo,but requiredin vitrothe addition of retinoic acid. The generation of differentiated notochord structures could only be obtained, if either older node grafts were usedin vitroor young node grafts were transplanted close to the primary axisin vivo.We conclude thatCNOTexpression in the anterior streak is not enough for notochord differentiation, but further influences are necessary. ANot-related gene has previously been isolated fromDrosophila melanogasterand its expression was detected in the posterior brain and the neuroblasts (Dessain and McGinnis, 1993.Adv. Dev. Biochem.2, 1–55). The correspondence betweenNotgene-expressing cells in the nervous system ofDrosophilaand the early neuroectoderm in the chick and its implication for a phylogenetic relationship between neuroectoderm and the notochord is discussed
Tbx6,a Mouse T-Box Gene Implicated in Paraxial Mesoderm Formation at Gastrulation

AbstractThe T-box genes constitute an evolutionarily conserved family of putative transcription factors which are expressed in discrete domains during embryogenesis, suggesting that they may play roles in inductive interactions. Members have been identified by virtue of their homology to the prototypical T-box gene,TorBrachyury,which is required for mesoderm formation and axial elongation during embryogenesis. We have previously reported the discovery of six new mouse T-box genes,Tbx1–Tbx6,and described the expression patterns ofTbx1–Tbx5(Bollaget al.,1994; Agulniket al.,1996; Chapmanet al.,1996; Gibson-Brownet al.,1996). We have obtained cDNA clones encoding the full-length Tbx6 protein from screens of gastrulation-stage mouse cDNA libraries and determined the spatial and temporal distribution ofTbx6transcripts during embryogenesis. The gene codes for a 1.9-kb transcript with an open reading frame coding for a 540-amino acid protein, with a predicted molecular weight of 59 kDa.Tbx6maps to chromosome 7 and does not appear to be linked to any known mutation. Unlike other members of the mouse T-box gene family which are expressed in a wide variety of tissues derived from all germ layers,Tbx6expression is quite restricted.Tbx6transcripts are first detected in the gastrulation stage embryo in the primitive streak and newly recruited paraxial mesoderm. Later in development,Tbx6expression is restricted to presomitic, paraxial mesoderm and to the tail bud, which replaces the streak as the source of mesoderm. Expression in the tail bud persists until 12.5 days postcoitus.Tbx6expression thus overlaps that ofBrachyuryin the primitive streak and tail bud, althoughBrachyuryis expressed earlier in the primitive streak.Brachyuryis also expressed in a second domain, the node and notochord, that is not shared withTbx6.The onset ofTbx6expression is not affected in homozygous nullBrachyurymutant embryos at 7.5 days postcoitus. However,Tbx6expression is extinguished in mutant embryos as soon as theBrachyuryphenotype becomes evident at 8.5 days postcoitus, indicating that the continued expression ofTbx6is directly or indirectly dependent uponBrachyuryexpression
Lens-Specific Expression of PDGF-A Alters Lens Growth and Development

AbstractThe vertebrate lens provides anin vivomodel to study the molecular mechanisms by which growth factors influence development decisions. In this study, we have investigated the expression patterns of platelet-derived growth factor (PDGF) and PDGF receptors during murine eye development byin situhybridization. Postnatally, PDGF-A is highly expressed in the iris and ciliary body, the ocular tissues closest to the germinative zone of the lens, a region where most proliferation of lens epithelial cells occurs. PDGF-A is also present in the corneal endothelium anterior to the lens epithelium in embryonic and early postnatal eyes. PDGF-B is expressed in the iris and ciliary body as well as in the vascular cells which surround the lens during early eye development. In the lens, expression of PDGF-α receptor (PDGF-αR), a receptor that can bind both PDGF-A and PDGF-B, is restricted to the lens epithelium throughout life. The expression of PDGF-αR in the lens epithelial cells and PDGF (A- and B-chains) in the ocular tissues adjacent to the lens suggests that PDGF signaling may play a key role in regulating lens development. To further examine how PDGF affects lens developmentin vivo,we generated transgenic mice that express human PDGF-A in the lens under the control of the αA-crystallin promoter. The transgenic mice exhibit lenticular defects that result in cataracts. The percentage of surface epithelial cells in S-phase is increased in transgenic lenses compared to their nontransgenic littermates. Higher than normal levels of cyclin A and cyclin D2 expression were also detected in transgenic lens epithelium. These results together suggest that PDGF-A can induce a proliferative response in lens epithelial cells. The lens epithelial cells in the transgenic mice also exhibit characteristics of differentiating fiber cells. For example, the transgenic lens epithelial cells are slightly elongated, contain larger and less condensed nuclei, and express fiber-cell-specific β-crystallins. Our results suggest that PDGF-A normally acts as a proliferative factor for the lens epithelial cellsin vivo.Elevated levels of PDGF-A enhance proliferation, but also appear to induce some aspects of the fiber cell differentiation pathway