DOCSLIB.ORG

Directing Human Embryonic Stem Cell Differentiation Towards a Renal Lineage Generates a Self-Organizing Kidney

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Directing Human Embryonic Stem Cell Differentiation Towards a Renal Lineage Generates a Self-Organizing Kidney LETTER Directing human embryonic stem cell differentiation towards a renal lineage generates a self-organizing kidney M. Takasato1, P. X. Er1, M. Becroft1, J. M. Vanslambrouck1, E. G. Stanley2,3, A. G. Elefanty2,3 and M. H. Little1,4 With the prevalence of end-stage renal disease rising 8% per initially arises from the posterior primitive streak, we first examined annum globally1, there is an urgent need for renal regenerative whether hESCs responded to these morphogens in a similar way strategies. The kidney is a mesodermal organ that differentiates to mice. We have previously shown that 20:100 (ng ml−1) of from the intermediate mesoderm (IM) through the formation of BMP4/activin A induced GFPC primitive streak from the reporter a ureteric bud (UB) and the interaction between this bud and hESC line MIXL1GFP/wt, in which GFP is knocked into the MIXL1 the adjacent IM-derived metanephric mesenchyme2 (MM). The gene locus, a robust marker of primitive streak11. Using this nephrons arise from a nephron progenitor population derived reporter line in monolayer culture, we tested several combinations from the MM (ref. 3). The IM itself is derived from the posterior of BMP4 and activin A (5:200, 20:100, 30:10, 30:0 and 0 V 0 ng ml−1) primitive streak4. Although the developmental origin of the or varying concentrations of a canonical Wnt signalling agonist, kidney is well understood2, nephron formation in the human CHIR99021 (5, 7, 9 µM) for optimal differentiation. All in vitro kidney is completed before birth5. Hence, there is no postnatal experiments were performed under chemically defined serum-free stem cell able to replace lost nephrons. In this study, we have culture conditions12. Comparative expression of MIXL1, T (posterior successfully directed the differentiation of human embryonic primitive streak) and SOX17 (anterior primitive streak) suggested that stem cells (hESCs) through posterior primitive streak and IM high BMP4/low activin A (30:10) or high CHIR99021 (>7 µM) was under fully chemically defined monolayer culture conditions optimal for posterior primitive streak (Fig.1 c,d and Supplementary using growth factors used during normal embryogenesis. This Fig. 1a–c). Under both conditions, approximately 90% of cells differentiation protocol results in the synchronous induction of became GFPC (Fig.1 b). UB and MM that forms a self-organizing structure, including The second stage of differentiation was to induce IM from primitive nephron formation, in vitro. Such hESC-derived components streak. After gastrulation, the definitive mesoderm can give rise to IM, show broad renal potential ex vivo, illustrating the potential for paraxial (PM) and lateral plate mesoderm (LPM). Previous studies pluripotent-stem-cell-based renal regeneration. investigating renal differentiation of pluripotent cells have relied on OSR1 as a definitive marker of IM and even MM formation13. However, On the basis of described embryology, we have defined a three-stage OSR1 expression is seen in trunk mesoderm and extends into LPM framework for the differentiation of hESCs to the key cellular (ref. 14). Spontaneous differentiation after initial induction of primitive compartments of the developing kidney, including genes that mark streak (BMP4/activin A (30:10), 3 days) showed OSR1 expression or exclude a specific end result6 (Fig.1 a). The primitive streak, (Supplementary Fig. 1d) but no evidence of more definitive IM markers, the progenitor population for both mesoderm and endoderm, can PAX2 and LHX1 (refs 14–16), by either PCR with reverse transcription be induced from mouse ESCs (mESCs) using activin A (ref. 7) (RT–PCR) or immunofluorescence. This indicated a need for further with opposing gradients of BMP4 and activin A specifying anterior growth factors to appropriately direct the next stage. FGF signalling (endoderm) versus posterior (mesoderm) primitive streak in mice8,9. was one possible requirement. FGF8 is expressed from primitive Canonical Wnt signalling has also been reported as an inducer streak through to posterior trunk mesoderm and FGF9 is expressed for primitive streak in mESCs and hESCs (refs 7,10). As the IM in IM and PM (refs 17,18). MM survival in vitro is supported by 1Institute for Molecular Bioscience, The University of Queensland, St Lucia 4072, Queensland, Australia. 2Murdoch Childrens Research Institute, The Royal Children's Hospital, Flemington Road, Parkville 3052, Victoria, Australia. 3Department of Anatomy and Developmental Biology, Monash University, Wellington Road, Clayton 3800, Victoria, Australia. 4Correspondence should be addressed to M.H.L. (e-mail: [email protected]) Received 23 January 2013; accepted 18 November 2013; published online 15 December 2013; DOI: 10.1038/ncb2894 118 NATURE CELL BIOLOGY VOLUME 16 j NUMBER 1 j JANUARY 2014 © 2014 Macmillan Publishers Limited. All rights reserved LETTER abc Ectoderm No GFs 20:100 30:10 Day 3 0% 92.3% 89.1% 2.0 SOX1 Endoderm T PAX6 MIXL1 OCT4 1.5 FOXA2 NANOG SOX17 SOX17 MIXL1–GFP 1.0 T Metanephric µ SIX2 hESCs No GFs 8 M CHIR HESC MIXL1 mesenchyme WT1 0.1% 0.2% 96.4% 0.5 Primitive PAX2 Relative gene LHX1 streak expression to 20:100 0 HOXB7 Intermediate GATA3 Ureteric 0:0 30:0 MIXL1–GFP mesoderm 30:10 5:200 hESCs epithelium FSC 20:100 deh30 BMP4/10 ActA PAX2 DAPI PAX2 LHX1 200 FGF9 or 8 CHIR T Day 3 0 2 6 (Days) 2.0 MIXL1 M –FGF9 µ SOX17 fg 1.5 B/A CHIR FGF9 1.0 –+ 100 PAX2 80 0.5 60 Relative gene LHX1 40 expression to 7 expression 0 OSR1 µ µ µ 20 +FGF9 (B/A) hESCs No GFs 5 M7 M9 M cells PAX2+ GAPDH of Percentage 0 –++ FGF9 n = 5 i Day 6 j Day 6 2,500 2,000 PAX2 +FGF9 (CHIR) PAX2 FOXF1 2,000 LHX1 LHX1 TBX6 1,500 FOXF1 k 1,500 TBX6 1,000 TBX6 1,000 to hESCs to hESCs 500 500 Relative expression PAX2 Relative expression 0 0 hESCs 200 200 200 200 200 FGF9 hESCs 0 10 50 200 400 250 25 –– –NOG –1 (ng ml FGF9) –––550BMP4 (ng ml–1) Figure 1 Sequential differentiation of primitive streak and intermediate positive for PAX2 protein at day 6 in the presence or absence of 200 ng ml−1 mesoderm from human ESCs. (a) Schematic of developmental stages from FGF9 from day 2–6. Both differentiation protocols using BMP4/activin A inner cell mass to renal lineages. Genes shown in each stage represent (B/A) and CHIR99021 (CHIR) exceeded 80% induction efficiency. Error specific markers of that stage. (b) FACS analysis (GFP and forward scatter bars are s.d. (n D 5 fields in total from 3 experiments). (h) The presence (FSC)) showing the percentage of MIXL1–GFP-positive primitive streak and co-expression of PAX2 (red) and LHX1 (green) proteins at day 6 through cells induced with different ratios of BMP4/activin A (ng ml−1) or 8 µM of primitive streak induction using either BMP4/activin A (B/A) or CHIR99021 CHIR99021 after 3 days of culture. hESC, starting cells; No GFs (growth (CHIR). Scale bars, 100 µm. (i) qRT–PCR showing the expression of markers factors), 3 days culture with basal media. (c) Relative expression levels of IM (PAX2, LHX1), PM (TBX6) and LPM (FOXF1) at day 6 across a of SOX17, brachyury (T ) and MIXL1 at day 3 for each ratio of BMP4 and concentration gradient of FGF9 from day 2 to 6. Error bars are s.d. (n D 3 activin A (ng ml−1) assessed by qRT–PCR analysis). (d) The same qRT–PCR experiments). (j) qRT–PCR showing the expression change of mesoderm analysis for different concentrations of CHIR99021. Error bars are s.d. markers at day 6 in the presence of FGF9 together with NOG or BMP4 from (n D 3 experiments). (e) Schematic representation of the differentiation day 2 to 6. Error bars are s.d. (n D 3 experiments). (k) Immunofluorescence protocol used from hESC to IM. (f) RT–PCR at day 6 showing the expression at day 6 showing a major IM population marked by PAX2 (red) and a of markers of IM (PAX2, LHX1, OSR1) in the presence or absence of non-overlapping PM marked by TBX6 (green). Scale bars, 100 µm. The 200 ng ml−1 FGF9 from day 2–6. (g) Quantification of the percentage of cells source data for graphs are provided in Supplementary Table 1. culture in either FGF2/BMP7 (ref. 19) or FGF9 (ref. 20). We therefore dose dependent (optimal at 200 ng ml−1) with suppression of the LPM tested the capacity of three FGF family members, FGF2, FGF8 and markers, FOXF1 (Fig.1 i) and OSR1 (Supplementary Fig. 2b). Cellular FGF9, to induce IM from posterior primitive streak. hESC-induced co-localization of PAX2 and OSR1 proteins was observed after initial posterior primitive streak was treated with 200 ng ml−1 of FGF2, induction with either BMP4/activin A or CHIR99021 followed by FGF9, 8 or 9 for 4 days before analysis using immunofluorescence and with LHX1 and PAX2 proteins co-localized in 79.5% (±4.7% s.d.; quantitative RT–PCR (qRT–PCR) (Fig.1 e). In the presence of FGF2 n D 5) of cells (Supplementary Fig. 2c,d). Hence, an FGF signal is or FGF9, but not FGF8, OSR1, PAX2 and LHX1 were co-expressed sufficient to efficiently specify IM after posterior primitive streak. In with >80% of cells PAX2C, suggesting differential IM induction early mesoderm development, BMP signalling is the key morphogen (Fig.1 f–h). PAX2 and LHX1 induction in response to FGF2 or FGF9 regulating lateral–medial patterning. Low BMP4 induces IM whereas was markedly inhibited by PD173074, a chemical inhibitor for FGFR1 high BMP4 induces LPM and NOG (noggin)-mediated antagonism and FGFR3 (Supplementary Fig.
Load more

Recommended publications
  • 3 Embryology and Development
    BIOL 6505 − INTRODUCTION TO FETAL MEDICINE 3. EMBRYOLOGY AND DEVELOPMENT Arlet G. Kurkchubasche, M.D. INTRODUCTION Embryology – the field of study that pertains to the developing organism/human Basic embryology –usually taught in the chronologic sequence of events. These events are the basis for understanding the congenital anomalies that we encounter in the fetus, and help explain the relationships to other organ system concerns. Below is a synopsis of some of the critical steps in embryogenesis from the anatomic rather than molecular basis. These concepts will be more intuitive and evident in conjunction with diagrams and animated sequences. This text is a synopsis of material provided in Langman’s Medical Embryology, 9th ed. First week – ovulation to fertilization to implantation Fertilization restores 1) the diploid number of chromosomes, 2) determines the chromosomal sex and 3) initiates cleavage. Cleavage of the fertilized ovum results in mitotic divisions generating blastomeres that form a 16-cell morula. The dense morula develops a central cavity and now forms the blastocyst, which restructures into 2 components. The inner cell mass forms the embryoblast and outer cell mass the trophoblast. Consequences for fetal management: Variances in cleavage, i.e. splitting of the zygote at various stages/locations - leads to monozygotic twinning with various relationships of the fetal membranes. Cleavage at later weeks will lead to conjoined twinning. Second week: the week of twos – marked by bilaminar germ disc formation. Commences with blastocyst partially embedded in endometrial stroma Trophoblast forms – 1) cytotrophoblast – mitotic cells that coalesce to form 2) syncytiotrophoblast – erodes into maternal tissues, forms lacunae which are critical to development of the uteroplacental circulation.
    [Show full text]
  • The Rotated Hypoblast of the Chicken Embryo Does Not Initiate an Ectopic Axis in the Epiblast
    Proc. Natl. Acad. Sci. USA Vol. 92, pp. 10733-10737, November 1995 Developmental Biology The rotated hypoblast of the chicken embryo does not initiate an ectopic axis in the epiblast ODED KHANER Department of Cell and Animal Biology, The Hebrew University, Jerusalem, Israel 91904 Communicated by John Gerhart, University of California, Berkeley, CA, July 14, 1995 ABSTRACT In the amniotes, two unique layers of cells, of the hypoblast and that the orientation of the streak and axis the epiblast and the hypoblast, constitute the embryo at the can be predicted from the polarity of the stage XIII epiblast. blastula stage. All the tissues of the adult will derive from the Still it was thought that the polarity of the epiblast is sufficient epiblast, whereas hypoblast cells will form extraembryonic for axial development in experimental situations, although in yolk sac endoderm. During gastrulation, the endoderm and normal development the polarity of the hypoblast is dominant the mesoderm of the embryo arise from the primitive streak, (5, 6). These reports (1-3, 5, 6), taken together, would imply which is an epiblast structure through which cells enter the that cells of the hypoblast not only have the ability to change interior. Previous investigations by others have led to the the fate of competent cells in the epiblast to initiate an ectopic conclusion that the avian hypoblast, when rotated with regard axis, but also have the ability to repress the formation of the to the epiblast, has inductive properties that can change the original axis in committed cells of the epiblast. At the same fate of competent cells in the epiblast to form an ectopic time, the results showed that the epiblast is not wholly depen- embryonic axis.
    [Show full text]
  • Gastrulation
    Embryology of the spine and spinal cord Andrea Rossi, MD Neuroradiology Unit Istituto Giannina Gaslini Hospital Genoa, Italy [email protected] LEARNING OBJECTIVES: LEARNING OBJECTIVES: 1) To understand the basics of spinal 1) To understand the basics of spinal cord development cord development 2) To understand the general rules of the 2) To understand the general rules of the development of the spine development of the spine 3) To understand the peculiar variations 3) To understand the peculiar variations to the normal spine plan that occur at to the normal spine plan that occur at the CVJ the CVJ Summary of week 1 Week 2-3 GASTRULATION "It is not birth, marriage, or death, but gastrulation, which is truly the most important time in your life." Lewis Wolpert (1986) Gastrulation Conversion of the embryonic disk from a bilaminar to a trilaminar arrangement and establishment of the notochord The three primary germ layers are established The basic body plan is established, including the physical construction of the rudimentary primary body axes As a result of the movements of gastrulation, cells are brought into new positions, allowing them to interact with cells that were initially not near them. This paves the way for inductive interactions, which are the hallmark of neurulation and organogenesis Day 16 H E Day 15 Dorsal view of a 0.4 mm embryo BILAMINAR DISK CRANIAL Epiblast faces the amniotic sac node Hypoblast Primitive pit (primitive endoderm) faces the yolk sac Primitive streak CAUDAL Prospective notochordal cells Dias Dias During
    [Show full text]
  • The Genetic Basis of Mammalian Neurulation
    REVIEWS THE GENETIC BASIS OF MAMMALIAN NEURULATION Andrew J. Copp*, Nicholas D. E. Greene* and Jennifer N. Murdoch‡ More than 80 mutant mouse genes disrupt neurulation and allow an in-depth analysis of the underlying developmental mechanisms. Although many of the genetic mutants have been studied in only rudimentary detail, several molecular pathways can already be identified as crucial for normal neurulation. These include the planar cell-polarity pathway, which is required for the initiation of neural tube closure, and the sonic hedgehog signalling pathway that regulates neural plate bending. Mutant mice also offer an opportunity to unravel the mechanisms by which folic acid prevents neural tube defects, and to develop new therapies for folate-resistant defects. 6 ECTODERM Neurulation is a fundamental event of embryogenesis distinct locations in the brain and spinal cord .By The outer of the three that culminates in the formation of the neural tube, contrast, the mechanisms that underlie the forma- embryonic (germ) layers that which is the precursor of the brain and spinal cord. A tion, elevation and fusion of the neural folds have gives rise to the entire central region of specialized dorsal ECTODERM, the neural plate, remained elusive. nervous system, plus other organs and embryonic develops bilateral neural folds at its junction with sur- An opportunity has now arisen for an incisive analy- structures. face (non-neural) ectoderm. These folds elevate, come sis of neurulation mechanisms using the growing battery into contact (appose) in the midline and fuse to create of genetically targeted and other mutant mouse strains NEURAL CREST the neural tube, which, thereafter, becomes covered by in which NTDs form part of the mutant phenotype7.At A migratory cell population that future epidermal ectoderm.
    [Show full text]
  • Understanding Paraxial Mesoderm Development and Sclerotome Specification for Skeletal Repair Shoichiro Tani 1,2, Ung-Il Chung2,3, Shinsuke Ohba4 and Hironori Hojo2,3
    Tani et al. Experimental & Molecular Medicine (2020) 52:1166–1177 https://doi.org/10.1038/s12276-020-0482-1 Experimental & Molecular Medicine REVIEW ARTICLE Open Access Understanding paraxial mesoderm development and sclerotome specification for skeletal repair Shoichiro Tani 1,2, Ung-il Chung2,3, Shinsuke Ohba4 and Hironori Hojo2,3 Abstract Pluripotent stem cells (PSCs) are attractive regenerative therapy tools for skeletal tissues. However, a deep understanding of skeletal development is required in order to model this development with PSCs, and for the application of PSCs in clinical settings. Skeletal tissues originate from three types of cell populations: the paraxial mesoderm, lateral plate mesoderm, and neural crest. The paraxial mesoderm gives rise to the sclerotome mainly through somitogenesis. In this process, key developmental processes, including initiation of the segmentation clock, formation of the determination front, and the mesenchymal–epithelial transition, are sequentially coordinated. The sclerotome further forms vertebral columns and contributes to various other tissues, such as tendons, vessels (including the dorsal aorta), and even meninges. To understand the molecular mechanisms underlying these developmental processes, extensive studies have been conducted. These studies have demonstrated that a gradient of activities involving multiple signaling pathways specify the embryonic axis and induce cell-type-specific master transcription factors in a spatiotemporal manner. Moreover, applying the knowledge of mesoderm development, researchers have attempted to recapitulate the in vivo development processes in in vitro settings, using mouse and human PSCs. In this review, we summarize the state-of-the-art understanding of mesoderm development and in vitro modeling of mesoderm development using PSCs. We also discuss future perspectives on the use of PSCs to generate skeletal tissues for basic research and clinical applications.
    [Show full text]
  • Sonic Hedgehog a Neural Tube Anti-Apoptotic Factor 4013 Other Side of the Neural Plate, Remaining in Contact with Midline Cells, RESULTS Was Used As a Control
    Development 128, 4011-4020 (2001) 4011 Printed in Great Britain © The Company of Biologists Limited 2001 DEV2740 Anti-apoptotic role of Sonic hedgehog protein at the early stages of nervous system organogenesis Jean-Baptiste Charrier, Françoise Lapointe, Nicole M. Le Douarin and Marie-Aimée Teillet* Institut d’Embryologie Cellulaire et Moléculaire, CNRS FRE2160, 49bis Avenue de la Belle Gabrielle, 94736 Nogent-sur-Marne Cedex, France *Author for correspondence (e-mail: [email protected]) Accepted 19 July 2001 SUMMARY In vertebrates the neural tube, like most of the embryonic notochord or a floor plate fragment in its vicinity. The organs, shows discreet areas of programmed cell death at neural tube can also be recovered by transplanting it into several stages during development. In the chick embryo, a stage-matched chick embryo having one of these cell death is dramatically increased in the developing structures. In addition, cells engineered to produce Sonic nervous system and other tissues when the midline cells, hedgehog protein (SHH) can mimic the effect of the notochord and floor plate, are prevented from forming by notochord and floor plate cells in in situ grafts and excision of the axial-paraxial hinge (APH), i.e. caudal transplantation experiments. SHH can thus counteract a Hensen’s node and rostral primitive streak, at the 6-somite built-in cell death program and thereby contribute to organ stage (Charrier, J. B., Teillet, M.-A., Lapointe, F. and Le morphogenesis, in particular in the central nervous system. Douarin, N. M. (1999). Development 126, 4771-4783). In this paper we demonstrate that one day after APH excision, Key words: Apoptosis, Avian embryo, Cell death, Cell survival, when dramatic apoptosis is already present in the neural Floor plate, Notochord, Quail/chick, Shh, Somite, Neural tube, tube, the latter can be rescued from death by grafting a Spinal cord INTRODUCTION generally induces an inflammatory response.
    [Show full text]
  • The Derivatives of Three-Layered Embryo (Germ Layers)
    HUMANHUMAN EMBRYOLOGYEMBRYOLOGY Department of Histology and Embryology Jilin University ChapterChapter 22 GeneralGeneral EmbryologyEmbryology FourthFourth week:week: TheThe derivativesderivatives ofof trilaminartrilaminar germgerm discdisc Dorsal side of the germ disc. At the beginning of the third week of development, the ectodermal germ layer has the shape of a disc that is broader in the cephalic than the caudal region. Cross section shows formation of trilaminar germ disc Primitive pit Drawing of a sagittal section through a 17-day embryo. The most cranial portion of the definitive notochord has formed. ectoderm Schematic view showing the definitive notochord. horizon =ectoderm hillside fields =neural plate mountain peaks =neural folds Cave sinks into mountain =neural tube valley =neural groove 7.1 Derivatives of the Ectodermal Germ Layer 1) Formation of neural tube Notochord induces the overlying ectoderm to thicken and form the neural plate. Cross section Animation of formation of neural plate When notochord is forming, primitive streak is shorten. At meanwhile, neural plate is induced to form cephalic to caudal end, following formation of notochord. By the end of 3rd week, neural folds and neural groove are formed. Neural folds fuse in the midline, beginning in cervical region and Cross section proceeding cranially and caudally. Neural tube is formed & invade into the embryo body. A. Dorsal view of a human embryo at approximately day 22. B. Dorsal view of a human embryo at approximately day 23. The nervous system is in connection with the amniotic cavity through the cranial and caudal neuropores. Cranial/anterior neuropore Neural fold heart Neural groove endoderm caudal/posterior neuropore A.
    [Show full text]
  • The Origin of Early Primitive Streak 89
    Development 127, 87-96 (2000) 87 Printed in Great Britain © The Company of Biologists Limited 2000 DEV3080 Formation of the avian primitive streak from spatially restricted blastoderm: evidence for polarized cell division in the elongating streak Yan Wei and Takashi Mikawa* Department of Cell Biology, Cornell University Medical College, 1300 York Avenue, New York, NY 10021, USA *Author for correspondence (e-mail: [email protected]) Accepted 13 October; published on WWW 8 December 1999 SUMMARY Gastrulation in the amniote begins with the formation of a cells generated daughter cells that underwent a polarized primitive streak through which precursors of definitive cell division oriented perpendicular to the anteroposterior mesoderm and endoderm ingress and migrate to their embryonic axis. The resulting daughter cell population was embryonic destinations. This organizing center for amniote arranged in a longitudinal array extending the complete gastrulation is induced by signal(s) from the posterior length of the primitive streak. Furthermore, expression of margin of the blastodisc. The mode of action of these cVg1, a posterior margin-derived signal, at the anterior inductive signal(s) remains unresolved, since various marginal zone induced adjacent epiblast cells, but not those origins and developmental pathways of the primitive streak lateral to or distant from the signal, to form an ectopic have been proposed. In the present study, the fate of primitive streak. The cVg1-induced epiblast cells also chicken blastodermal cells was traced for the first time in exhibited polarized cell divisions during ectopic primitive ovo from prestreak stages XI-XII through HH stage 3, streak formation. These results suggest that blastoderm when the primitive streak is initially established and prior cells located immediately anterior to the posterior marginal to the migration of mesoderm.
    [Show full text]
  • Nephric Lineage Specification by Pax2 and Pax8
    Downloaded from genesdev.cshlp.org on September 28, 2021 - Published by Cold Spring Harbor Laboratory Press Nephric lineage specification by Pax2 and Pax8 Maxime Bouchard, Abdallah Souabni, Markus Mandler, Annette Neubüser, and Meinrad Busslinger1 Research Institute of Molecular Pathology, Vienna Biocenter, A-1030 Vienna, Austria The mammalian kidney develops in three successive steps from the initial pronephros via the mesonephros to the adult metanephros. Although the nephric lineage is specified during pronephros induction, no single regulator, including the transcription factor Pax2 or Pax8, has yet been identified to control this initial phase of kidney development. In this paper, we demonstrate that mouse embryos lacking both Pax2 and Pax8 are unable to form the pronephros or any later nephric structures. In these double-mutant embryos, the intermediate mesoderm does not undergo the mesenchymal-epithelial transitions required for nephric duct formation, fails to initiate the kidney-specific expression of Lim1and c -Ret, and is lost by apoptosis 1d after failed pronephric induction. Conversely, retroviral misexpression of Pax2 was sufficient to induce ectopic nephric structures in the intermediate mesoderm and genital ridge of chick embryos. Together, these data identify Pax2 and Pax8 as critical regulators that specify the nephric lineage. [Keywords: Pax2;Pax8;genetic redundancy;kidney development;mesenchymal-epithelial transition;lineage specification] Received June 28, 2002;revised version accepted September 20, 2002. Kidney development in mammals and birds proceeds in development (for review, see Kuure et al. 2000;Davies three successive steps that are all characterized by the and Brändli 2002). The majority of these genes are essen- mesenchymal-to-epithelial transformation of intermedi- tial for proper morphogenesis of the metanephros with ate mesoderm cells.
    [Show full text]
  • Mesoderm Divided Into Three Main Types - Paraxial (Somite) - Intermediate - Lateral (Somatic and Splanchnic)
    Mesoderm Divided into three main types - Paraxial (somite) - Intermediate - Lateral (somatic and splanchnic) Fates of Mesoderm Paraxial - Dermis of skin - Axial Skeleton - Axial and limb muscles/tendons Intermediate - Urogenital system (kidney and gonads) Lateral - Somatic inner body wall (connective), pelvis, limb bones (parietal) - Splanchnic heart and vasculature (visceral) Paraxial (somitic) Mesoderm Head Region - Head mesoderm + neural crest forms: skeleton, muscles, and conntective tissue of the face and skull Trunk Region - Forms somites, which will produce: muscle, bone and dermis Two Cell Types: Epithelial: regular, simple sheet of cells, immobile Mesenchyma: irregular and migratory These two cell types can undergo transformation into one another. Somitogenisis (Somite Formation) Somites form progressively from cranial to caudal end of the notochord in a sequential fashion. One closes before the next forms. Somite Differentiation The somite splits into the epithelial dermamyotome (dermis/muscle) and the messenchymal sclerotome (skeletal). The somite is all paraxial mesoderm. Somite location determines the fate of its associates derma/myo/sclerotomes. Intermediate Mesoderm Urogenital system: - Kidneys - Gonads - Reproductive Duct Systems Runs alongside the paraxial mesoderm. Urogenital System Along mesonephric duct: - Pronephros, mesonephros, and metanephros - Pronephros fall away as gonad develops on ventral-medial side of mesonephros. - Metanephrogenic mesenchyme gives rise to kidney. The mesonephric duct will become the Wolffian duct forming at the nephric bud. The Mullerian duct forms via an invagination on the dorsal side of the nephric duct. The gonad will degenerate one of the two ducts depending on the hormones it produces. XX degenerates Wolffian duct – no testosterone, anti-Mullerian hormone (AMH) not produced, and Mullerian duct can develop in addition to female reproductive organs (ovaries, vagina) XY degenerates Mullerian duct – testosterone, AMH produced, Wolffian duct continues as male reproductive organs (testes, penis) develop.
    [Show full text]
  • A Review of Primitive Streak Formation and Somitogenesis
    SPATIOTEMPORAL PATTERN FORMATION IN EARLY DEVELOPMENT: A REVIEW OF PRIMITIVE STREAK FORMATION AND SOMITOGENESIS S. SCHNELL', K.J. PAINTERt, P.K. MAINI' , AND H.G. OTHMERt Abstract. The basic body plan of a number of vertebrates results from two pro­ cesses that occur early in the development of the blastoderm: large scale rearrangements of tissue via a process called gastrulation, and axial subdivision of tissue in a process called somitogenesis. The first step of gastrulation in avians is formation of the prim­ itive streak, which marks the first clear manifestation of the anterior-posterior axis. Cell movements that occur through the streak ultimately convert the single layered­ blastoderm into a trilaminar blastoderm comprising prospective endodermal, mesoder­ mal and ectodermal tissue. During streak formation a group of cells moves anteriorly as a coherent column from the posterior end of the blastoderm, and as it proceeds other cells stream over the lateral edges of the furrow left behind. The anterior end of the streak is a specialized structure called Hensen's node, which serves as an organizing center for later axis formation and determination of the left-right asymmetry of the body. Soon after the primitive streak forms, Hensen's node regresses towards the tail, leaving the notochord and a pair of segmental plates parallel to the primitive streak in its wake. The posterior end of the segmental plate moves down the cranio-caudal axis with the node, as more cells are added to it by cell division within the plate and by cells entering from the primitive streak. A pair of somites forms from the anterior ends of the two plates at regular intervals.
    [Show full text]
  • The Hypoblast (Visceral Endoderm): an Evo-Devo Perspective Claudio D
    REVIEW 1059 Development 139, 1059-1069 (2012) doi:10.1242/dev.070730 © 2012. Published by The Company of Biologists Ltd The hypoblast (visceral endoderm): an evo-devo perspective Claudio D. Stern1,* and Karen M. Downs2 Summary animals develop very quickly; their early cleavages occur without When amniotes appeared during evolution, embryos freed G1 or G2 phases and consist only of mitotic (M) and DNA synthetic themselves from intracellular nutrition; development slowed, (S) phases, and they rely upon maternal mRNAs and proteins until the mid-blastula transition was lost and maternal components zygotic gene expression is activated, usually at around the 11th cell became less important for polarity. Extra-embryonic tissues division (2024 cells). Rapid development and absence of growth emerged to provide nutrition and other innovations. One such imply that the embryonic axes or body plan must be set up quite tissue, the hypoblast (visceral endoderm in mouse), acquired a quickly, within about 24 hours of fertilization, and by subdivision of role in fixing the body plan: it controls epiblast cell movements the original mass of protoplasm, as seen in long germ band insects, leading to primitive streak formation, generating bilateral such as Drosophila. Because of the absence of early growth, the symmetry. It also transiently induces expression of pre-neural fertilized egg of anamniotes contains all the nutrients necessary to markers in the epiblast, which also contributes to delay streak sustain the embryo until it can feed itself, some time after hatching. formation. After gastrulation, the hypoblast might protect In amphibians, nutrition is provided by intracellular yolk, and in prospective forebrain cells from caudalizing signals.
    [Show full text]