DOCSLIB.ORG

Conserved Regulation in Limb and Face 223 Remove Any Non-Specifically Bound Probe

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Conserved Regulation in Limb and Face 223 Remove Any Non-Specifically Bound Probe Development 126, 221-228 (1999) 221 Printed in Great Britain © The Company of Biologists Limited 1998 DEV2331 Conserved regulation of mesenchymal gene expression by Fgf-8 in face and limb development Abigail S. Tucker1, Abdul Al Khamis1, Christine A. Ferguson1, Ingolf Bach2, Michael G. Rosenfeld2 and Paul T. Sharpe1,* 1Department of Craniofacial Development, GKT Dental Institute, Kings College, Guy’s Hospital, London SE1 9RT, UK 2Howard Hughes Medical Institute, Department and School of Medicine, University of California at San Diego, La Jolla, California, USA *Author for correspondence (e-mail: [email protected]) Accepted 5 November; published on WWW 14 December 1998 SUMMARY Clim-2 (NLI, Lbd1) is one of two related mouse proteins show that in the mandibular arch, as in the limb, Fgf-8 that interact with Lim-domain homeoproteins. In the functions in combination with CD44, a cell surface binding mouse, embryonic expression of Clim-2 is particularly protein, and that blocking CD44 binding results in pronounced in facial ectomesenchyme and limb bud inhibition of Fgf8-induced expression of Clim-2 and Lhx-6. mesenchyme in association with Lim genes, Lhx-6 and Regulation of gene expression by Fgf8 in association with Lmx-1 respectively. We show that in common with both CD44 is thus conserved between limb and mandibular arch these Lim genes, Clim-2 expression is regulated by signals development. from overlying epithelium. In both the developing face and the limb buds we identify Fgf-8 as the likely candidate Key words: LIM homeodomain, Clim-2, NLI, Ldb-1, Fgf-8, CD44, signalling molecule that regulates Clim-2 expression. We Branchial arch, Limb, Mouse INTRODUCTION thought to be similar to, or the same as Lhx-8 (L3)), are largely restricted to anterior mesenchymal cells of the mandibular and Early embryonic development of the facial processes and limb maxillary arches (Grigoriou et al., 1998; Wanaka et al., 1997; buds has been considered to share some common basic Kitanaka et al., 1998). Removal of the oral epithelium results mechanisms despite the mesenchymal cells having different in a downregulation of Lhx-6/-7 expression, which can be embryonic origins. The mesenchymal cells that contribute to rescued by the addition of Fgf-8 protein on beads (Grigoriou et oral and facial hard tissues are derived from cranial neural crest al., 1998). Since Fgf-8 is normally expressed in oral epithelium cells whereas limb mesenchyme cells are derived from axial it is an ideal candidate for the endogenous inducer of Lhx-6/-7. mesoderm. The outgrowth of facial processes has been Limb bud epithelium, a source of Fgf-8, is capable of inducing compared with limb bud outgrowth, and the tooth bud enamel Lhx-6/-7 expression in branchial arch mesenchyme cells but not knot has been identified as a signalling centre with similarities in limb bud mesenchyme cells, indicating that the neural crest to both the limb ZPA and AER signalling centres (Koyama, et origin of the mesenchymal cells determines their ability to al., 1996; Jernvall et al., 1994; Vaahtokari et al., 1996). In activate Lhx-6/-7 expression in response to Fgf-8 (Tucker et al., addition, several homeobox-containing genes have been 1999). The expression of Lmx-1 is restricted to the dorsal implicated in both branchial arch and limb development, such mesenchymal cells of the limb bud. Removal of the dorsal limb as members of the Msx, Dlx and Lim-homeobox families (Chen bud epithelium results in downregulation of Lmx-1 expression, et al., 1996; 1997; Bulfone et al., 1993; Ferrari et al., 1995; Qiu which can be rescued by ectopic expression of Wnt-7a, a gene et al., 1995; Grigoriou et al., 1998; Riddle et al., 1995). Msx-1 normally expressed in dorsal epithelium (Riddle et al., 1995). expression, for example, has been shown to be maintained in Overexpression of Lmx-1 results in limbs with a double dorsal face to limb mesenchyme grafts (Brown et al., 1993). phenotype, while loss of Lmx-1 expression, as seen in Wnt-7a The Lim domain is a specialised double-zinc finger motif mutant embryos, results in limbs with a double ventral found in a variety of proteins. Lim domains are thought to phenotype (Vogel et al., 1995; Cygan et al., 1997). Restricted function as protein interaction modules, and have important expression of both Lhx-6/-7 in facial mesenchyme and Lmx-1 functions in cell lineage determination and pattern formation in limb bud mesenchyme are thus under the control of specific (Dawid et al., 1998). Regulation of the Lim-homeobox genes but different signals from the overlying epithelium. in the face and limb has been shown to be under the control of In the mouse, the Clim family of proteins have been the epithelium. The expression of the Lim-domain gene Lhx-6, identified as interacting (co-factors) with Lim-domain proteins and its closely associated family member Lhx-7 (which is (Bach et al., 1997). Clim-2 (cofactor of Lim homeodomain 222 A. S. Tucker and others proteins 2) was identified by its ability to bind to the Lim were detected was considered as E0.5. Cultures were carried out at domain of Lhx-3 (Bach et al., 1997). It is also known in the E10.5. Mandibular arch and forelimb buds were dissected in D-MEM. mouse as Ldb-1 and NLI (Agulnick et al., 1996; Jurata et al., The epithelium was removed using Dispase in calcium- and 1996). Homologues are found in Xenopus (Xldb-1), Zebrafish magnesium-free PBS at 2 units per ml, for 10 minutes at 37°C. After (Zfldb-1-4) and Drosophila (Chip) (Agulnick et al., 1996; incubation the tissues were washed in D-MEM with 10% fetal calf Toyama et al., 1998; Morcillo et al., 1997), all of which have serum (FCS), and the epithelium was dissected using fine tungsten needles. The mesenchyme was placed on membrane filters supported been characterised by their interactions with Lim proteins. α by metal grids according to the Trowel technique as modified by Clim-2 is required for the synergistic activation of the GSU Saxén (Trowel, 1959; Saxén, 1966). For the recombinations, gene by other Lim homeodomain genes, but is unable to epithelium and mesenchyme were aligned in the correct orientation activate transcription itself (Bach et al., 1997). Thus Clim-2 is on top of transparent Nucleopore membrane filters (0.1 µm pore believed to be an essential co-activator of Lim protein function. diameter; Costar). For the bead experiments, limb buds and From work in Xenopus, it has been shown that Xldb-1 binds mandibular arches were placed on top of Millipore filters (0.1 µm pore the Lim domains through its carboxyl-terminal group and diameter) and beads added. For both these experiments it was forms homodimers via its amino-terminal region. Both regions important that the mandibular arch mesenchyme was facing oral side are necessary for the synergism of Ldb1 with Xlim-1 in the up. activation of downstream genes (Breen et al., 1998). For the Fgf and BSA control protein heparin, acrylic beads (Sigma) were used. These were washed several times in PBS, then incubated Misexpression of Clim-2 alone when injected into Xenopus overnight at 4°C in 1 µg/µl Fgf-8b, or Fgf-9 (R & D systems). For embryos had no obvious effect on development, whereas co- the BMP2 and 4 proteins, Affi-Gel-blue beads (Bio Rad) were used injection with Lhx-1 resulted in partial axis duplication, (Genetics Institute). These were washed and dried out before being indicating again that Clim-2 acts as a co-factor for LIM- placed in the protein for 1 hour at 37°C. The BMPs were used at a domain proteins (Agulnick et al., 1996). Similarly in chick concentration of 100 µg/ml, a concentration which has been shown to limb development, misexpression of Clim-2 using retroviruses induce Msx-1 and repress Pax-9 expression in a similar assay (Tucker has no effect on development (Bach et al., unpublished). et al., 1998; Neubüser et al., 1997). Protein-soaked beads were stored In the mouse, Clim-2 is detected from E8.5, at the time when at 4°C for up to 3 weeks. the Lim homeodomain genes are first starting to be expressed. The explants were cultured for 4-24 hours in D-MEM with 10% At E9.0-E9.5, high expression is seen in the brain, neural tube, FCS. A standard incubator was used at 37°C with an atmosphere of 5% CO2 in air and 100% humidity. All solutions used contained the forming branchial arches and limbs, overlapping with the penicillin and streptomycin at 20 IU/ml. After the period of culture, expression patterns of several Lim domain genes including, cultures were washed in ice-cold methanol for 1 minute then fixed in Lhx-2 (LH-2), Lhx-3 (P-Lim), Lhx-6, Lhx-7 (Lhx-8) and Lmx1 fresh 4% paraformaldehyde for 1 hour at RT. Cultures were then (Bach et al., 1997, Grigoriou et al., 1998; Wanaka et al., 1997; prepared for whole-mount digoxigenin in situ hybridisation. Kitanka et al., 1998; Riddle et al., 1995). We show that in common with Lhx-6 and Lmx-1, the epithelium is required for CD44 blocking experiments Clim-2 expression in underlying mesenchyme. However Clim- Digested oligosaccharide fragment preparations of hyaluronic acid 2 differs from the Lim-domain genes in that its expression is (HAOS) were prepared by treating hyaluronan with testicular regulated by the same signal, Fgf-8, in both the limb buds and hyaluronidase (40U/mg hyaluronan) for 4 hours in 0.2 M sodium mandibular arches.
Load more

Recommended publications
  • Wnt Signalling During Limb Development
    Int. J. Dev. Biol. 46: 927-936 (2002) Wnt signalling during limb development VICKI L. CHURCH and PHILIPPA FRANCIS-WEST* Department of Craniofacial Development, King’s College London, Guy’s Hospital, London, UK ABSTRACT Wnts control a number of processes during limb development - from initiating outgrowth and controlling patterning, to regulating cell differentiation in a number of tissues. Interactions of Wnt signalling pathway components with those of other signalling pathways have revealed new mechanisms of modulating Wnt signalling, which may explain how different responses to Wnt signalling are elicited in different cells. Given the number of Wnts that are expressed in the limb and their ability to induce differential responses, the challenge will be to dissect precisely how Wnt signalling is regulated and how it controls limb development at a cellular level, together with the other signalling pathways, to produce the functional limb capable of co- ordinated precise movements. KEY WORDS: Wnt, limb, development, chondrogenesis, myogenesis The Wnt Gene Family is found in the others (Cadigan and Nusse, 1997). The frizzled receptors can function together with the LRP co-receptors, which The Wnt family of secreted glycosylated factors consists of 22 are single transmembrane proteins containing LDL receptor re- members in vertebrates which have a range of functions during peats, two frizzled motifs and four EGF type repeats in the development from patterning individual structures to fine tuning at extracellular domain (reviewed by Pandur and Kühl, 2001; also see a cellular level controlling cell differentiation, proliferation and Roszmusz et al., 2001). The LRPs, which include the vertebrate survival. The founding members of this family are the Drosophila genes LRP4, -5 and -6 and the Drosophila gene arrow, form a segment polarity gene Wingless (Wg), required for wing develop- complex with frizzled in a Wnt-dependent manner and signal in the ment, together with Wnt1 (originally named int-1) in the mouse.
    [Show full text]
  • Hox Genes Regulate the Onset of Tbx5 Expression in the Forelimb Carolina Minguillon1,*,‡, Satoko Nishimoto1, Sophie Wood2, Elisenda Vendrell1, Jeremy J
    3180 RESEARCH ARTICLE Development 139, 3180-3188 (2012) doi:10.1242/dev.084814 © 2012. Published by The Company of Biologists Ltd Hox genes regulate the onset of Tbx5 expression in the forelimb Carolina Minguillon1,*,‡, Satoko Nishimoto1, Sophie Wood2, Elisenda Vendrell1, Jeremy J. Gibson-Brown3,§ and Malcolm P. O. Logan1,* SUMMARY Tbx4 and Tbx5 are two closely related T-box genes that encode transcription factors expressed in the prospective hindlimb and forelimb territories, respectively, of all jawed vertebrates. Despite their striking limb type-restricted expression pattern, we have shown that these genes do not participate in the acquisition of limb type-specific morphologies. Instead, Tbx4 and Tbx5 play similar roles in the initiation of hindlimb and forelimb outgrowth, respectively. We hypothesized that different combinations of Hox proteins expressed in different rostral and caudal domains of the lateral plate mesoderm, where limb induction occurs, might be involved in regulating the limb type-restricted expression of Tbx4 and Tbx5 and in the later determination of limb type-specific morphologies. Here, we identify the minimal regulatory element sufficient for the earliest forelimb-restricted expression of the mouse Tbx5 gene and show that this sequence is Hox responsive. Our results support a mechanism in which Hox genes act upstream of Tbx5 to control the axial position of forelimb formation. KEY WORDS: Tbx5, Hox, Limb development INTRODUCTION induce, and are markers of, forelimb and hindlimb outgrowth, T-box genes encode a family of transcription factors that have respectively, they do not play a role in the specification of limb been identified in all metazoans and which play diverse roles type-specific morphologies.
    [Show full text]
  • T-Box Genes in Limb Development and Disease
    Open Research Online The Open University’s repository of research publications and other research outputs T-box Genes in Limb Development and Disease Thesis How to cite: Rallis, Charalampos (2004). T-box Genes in Limb Development and Disease. PhD thesis The Open University. For guidance on citations see FAQs. c 2004 Charalampos Rallis Version: Version of Record Link(s) to article on publisher’s website: http://dx.doi.org/doi:10.21954/ou.ro.0000fa0b Copyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyright owners. For more information on Open Research Online’s data policy on reuse of materials please consult the policies page. oro.open.ac.uk T-box Genes in Limb Development and Disease Charalampos Rallis Thesis submitted for the degree of Doctor of Philosophy October 2004 Division of Developmental Biology National Institute for Medical Research Mill Hill London Open University ProQuest Number: C819643 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a com plete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest C819643 Published by ProQuest LLO (2019). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C ode Microform Edition © ProQuest LLO. ProQuest LLO. 789 East Eisenhower Parkway P.Q.
    [Show full text]
  • Pitx2 Determines Left–Right Asymmetry of Internal Organs in Vertebrates 8
    articles Pitx2 determines left–right asymmetry of internal organs in vertebrates 8 Aimee K. Ryan*†, Bruce Blumberg†‡, Concepcio´ n Rodriguez-Esteban†‡, Sayuri Yonei-Tamura†‡, Koji Tamura‡, Tohru Tsukui‡, Jennifer de la Pen˜ a‡, Walid Sabbagh‡, Jason Greenwald‡, Senyon Choe‡, Dominic P. Norris§, Elizabeth J. Robertson§, Ronald M. Evans‡k, Michael G. Rosenfeld* & Juan Carlos Izpisu´ a Belmonte‡ * Howard Hughes Medical Institute, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0648, USA § Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, Massachusetts 02138, USA k Howard Hughes Medical Institute, ‡ The Salk Institute, 10010 North Torrey Pines Road, La Jolla, California 92037, USA † These authors contributed equally to this work ........................................................................................................................................................................................................................................................ The handedness of visceral organs is conserved among vertebrates and is regulated by asymmetric signals relayed by molecules such as Shh, Nodal and activin. The gene Pitx2 is expressed in the left lateral plate mesoderm and, subsequently, in the left heart and gut of mouse, chick and Xenopus embryos. Misexpression of Shh and Nodal induces Pitx2 expression, whereas inhibition of activin signalling blocks it. Misexpression of Pitx2 alters the relative position of organs and the direction of
    [Show full text]
  • Wnt/Lef1 Signaling Acts Via Pitx2 to Regulate Somite Myogenesis
    Developmental Biology 337 (2010) 211–219 Contents lists available at ScienceDirect Developmental Biology journal homepage: www.elsevier.com/developmentalbiology Wnt/Lef1 signaling acts via Pitx2 to regulate somite myogenesis Muhammad Abu-Elmagd a, Lesley Robson b, Dylan Sweetman a, Julia Hadley c, Philippa Francis-West c,⁎, Andrea Münsterberg a,⁎ a University of East Anglia, School of Biological Sciences, Norwich, NR4 7TJ Earlham Road, UK b Queen Mary University of London, Neuroscience, Barts and The London SMD, E1 2AD London, UK c Craniofacial Development, The Dental Institute, King's College London, Guy's Campus, London, SE1 9RT, UK article info abstract Article history: Wnt signaling has been implicated in somite, limb, and branchial arch myogenesis but the mechanisms and Received for publication 23 February 2009 roles are not clear. We now show that Wnt signaling via Lef1 acts to regulate the number of premyogenic Revised 18 September 2009 cells in somites but does not regulate myogenic initiation in the limb bud or maintenance in the first or Accepted 14 October 2009 second branchial arch. We have also analysed the function and regulation of a putative downstream Available online 20 October 2009 transcriptional target of canonical Wnt signaling, Pitx2. We show that loss-of-function of Pitx2 decreases the Keywords: number of myogenic cells in the somite, whereas overexpression increases myocyte number particularly in Chicken embryo the epaxial region of the myotome. Increased numbers of mitotic cells were observed following Wnt signaling overexpression of Pitx2 or an activated form of Lef1, suggesting an effect on cell proliferation. In addition, Myogenesis we show that Pitx2 expression is regulated by canonical Wnt signaling in the epaxial somite and second Lef1 branchial arch, but not in the limb or the first branchial arch.
    [Show full text]
  • The Roles of Fgfs in the Early Development of Vertebrate Limbs
    Downloaded from genesdev.cshlp.org on September 26, 2021 - Published by Cold Spring Harbor Laboratory Press REVIEW The roles of FGFs in the early development of vertebrate limbs Gail R. Martin1 Department of Anatomy and Program in Developmental Biology, School of Medicine, University of California at San Francisco, San Francisco, California 94143–0452 USA ‘‘Fibroblast growth factor’’ (FGF) was first identified 25 tion of two closely related proteins—acidic FGF and ba- years ago as a mitogenic activity in pituitary extracts sic FGF (now designated FGF1 and FGF2, respectively). (Armelin 1973; Gospodarowicz 1974). This modest ob- With the advent of gene isolation techniques it became servation subsequently led to the identification of a large apparent that the Fgf1 and Fgf2 genes are members of a family of proteins that affect cell proliferation, differen- large family, now known to be comprised of at least 17 tiation, survival, and motility (for review, see Basilico genes, Fgf1–Fgf17, in mammals (see Coulier et al. 1997; and Moscatelli 1992; Baird 1994). Recently, evidence has McWhirter et al. 1997; Hoshikawa et al. 1998; Miyake been accumulating that specific members of the FGF 1998). At least five of these genes are expressed in the family function as key intercellular signaling molecules developing limb (see Table 1). The proteins encoded by in embryogenesis (for review, see Goldfarb 1996). Indeed, the 17 different FGF genes range from 155 to 268 amino it may be no exaggeration to say that, in conjunction acid residues in length, and each contains a conserved with the members of a small number of other signaling ‘‘core’’ sequence of ∼120 amino acids that confers a com- molecule families [including WNT (Parr and McMahon mon tertiary structure and the ability to bind heparin or 1994), Hedgehog (HH) (Hammerschmidt et al.
    [Show full text]
  • Patterning Mechanisms Controlling Vertebrate Limb Development
    8 Sep 2001 13:46 AR AR139-4.tex AR139-4.SGM ARv2(2001/05/10) P1: GSR Annu. Rev. Cell Dev. Biol. 2001. 17:87–132 Copyright c 2001 by Annual Reviews. All rights reserved PATTERNING MECHANISMS CONTROLLING VERTEBRATE LIMB DEVELOPMENT Javier Capdevila and Juan Carlos Izpisua´ Belmonte The Salk Institute for Biological Studies, Gene Expression Laboratory, 10010 North Torrey Pines Road, La Jolla, California 92037; e-mail: [email protected]; [email protected] Key Words AER, BMP, FGF, Hedgehog, limb, morphogen, pattern formation, regeneration, secreted factors, vertebrate development, WNT, ZPA ■ Abstract Vertebrate limb buds are embryonic structures for which much molecu- lar and cellular data are known regarding the mechanisms that control pattern formation during development. Specialized regions of the developing limb bud, such as the zone of polarizing activity (ZPA), the apical ectodermal ridge (AER), and the non-ridge ectoderm, direct and coordinate the development of the limb bud along the anterior- posterior (AP), dorsal-ventral (DV), and proximal-distal (PD) axes, giving rise to a stereotyped pattern of elements well conserved among tetrapods. In recent years, spe- cific gene functions have been shown to mediate the organizing and patterning activities of the ZPA, the AER, and the non-ridge ectoderm. The analysis of these gene functions has revealed the existence of complex interactions between signaling pathways oper- ated by secreted factors of the HH, TGF-/BMP, WNT, and FGF superfamilies, which interact with many other genetic networks to control limb positioning, outgrowth, and patterning. The study of limb development has helped to establish paradigms for the analysis of pattern formation in many other embryonic structures and organs.
    [Show full text]
  • Computational Modeling of Limb-Bud Dysmorphogenesis
    Computational Modeling of Limb-Bud Dysmorphogenesis: Predicting Cellular Dynamics and Key Events in Developmental Toxicity with a Multicellular Systems Model BK Ahir1, ES Hunter2, NC Baker3, RM Spencer3, RS Dewoskin4, TB Knudsen1 U.S. Environmental Protection Agency, Office of Research and Development Tom Knudsen | [email protected] l 919-541-9776 1National Center for Computational Toxicology, 2National Health and Environmental Effects Research Laboratory, 3Lockheed Martin, 4National Center for Environmental Assessment 1. COMPUTATIONAL EMBRYOLOGY & PREDICTIVE TOXICOLOGY 3. CELLULAR DYNAMICS: translation of spatial information 4. TOXICODYNAMICS: predicting key events HYPOTHESIS: CELL AGENT-BASED MODEL (ABM): multicellular and signaling dynamics were modeled in CHEMICAL DISRUPTION: How might local effects predicted by in vitro high-throughput screening CompuCell3D (www.compucell3d.org/); the small working prototype simulated mouse hindlimb-bud (HTS) data such as ToxCast™ propagate through the pivotal SHH cell lineage in silico to predict, a computer model that simulates cellular function in a growing development between Theiler stages 16-19 (~42h) in ~42,000 Monte Carlo Steps (MCS). therefore, a key event in vivo? embryo can be used to predict the potential impact of chemical EXAMPLE: 5-Fluorouracil, a teratogen that disrupts digit formation, perturbed 13 of 650 ToxCast HTS Cellular behaviors Signals assays at ≤ 15 µM: impaired differentiation and increased cell loss (excessive apoptosis); p53- exposure during early limb development. AER induction, mitotic arrest and cell death. These effects can be fed into the model for translation into Adhesion predicted outcomes. Apoptosis Differentiation Shh cell lineage (n=10) control 2. SIGNALING NETWORK: spatial information processing Migration excess apoptosis 38k Mitosis - mitotic arrest Shape mixed effect CONTROL exposed at exposed Query of Mouse Genome Informatics database (www.informatics.jax.org/) by ‘abnormal limb bud Size 32 MCS ZPA morphology’ (MP:0005650) returned genes for 132 relevant genotypes.
    [Show full text]
  • Transcriptomic and Epigenomic Characterization of the Developing Bat Wing
    ARTICLES OPEN Transcriptomic and epigenomic characterization of the developing bat wing Walter L Eckalbar1,2,9, Stephen A Schlebusch3,9, Mandy K Mason3, Zoe Gill3, Ash V Parker3, Betty M Booker1,2, Sierra Nishizaki1,2, Christiane Muswamba-Nday3, Elizabeth Terhune4,5, Kimberly A Nevonen4, Nadja Makki1,2, Tara Friedrich2,6, Julia E VanderMeer1,2, Katherine S Pollard2,6,7, Lucia Carbone4,8, Jeff D Wall2,7, Nicola Illing3 & Nadav Ahituv1,2 Bats are the only mammals capable of powered flight, but little is known about the genetic determinants that shape their wings. Here we generated a genome for Miniopterus natalensis and performed RNA-seq and ChIP-seq (H3K27ac and H3K27me3) analyses on its developing forelimb and hindlimb autopods at sequential embryonic stages to decipher the molecular events that underlie bat wing development. Over 7,000 genes and several long noncoding RNAs, including Tbx5-as1 and Hottip, were differentially expressed between forelimb and hindlimb, and across different stages. ChIP-seq analysis identified thousands of regions that are differentially modified in forelimb and hindlimb. Comparative genomics found 2,796 bat-accelerated regions within H3K27ac peaks, several of which cluster near limb-associated genes. Pathway analyses highlighted multiple ribosomal proteins and known limb patterning signaling pathways as differentially regulated and implicated increased forelimb mesenchymal condensation in differential growth. In combination, our work outlines multiple genetic components that likely contribute to bat wing formation, providing insights into this morphological innovation. The order Chiroptera, commonly known as bats, is the only group of To characterize the genetic differences that underlie divergence in mammals to have evolved the capability of flight.
    [Show full text]
  • Regulatory Modulation of the T-Box Gene Tbx5 Links Development, Evolution, and Adaptation of the Sternum
    Regulatory modulation of the T-box gene Tbx5 links development, evolution, and adaptation of the sternum Sorrel R. B. Bickleya and Malcolm P. O. Logana,b,1 aDivision of Developmental Biology, Medical Research Council-National Institute for Medical Research, London NW7 1AA, United Kingdom; and bRandall Division of Cell and Molecular Biophysics, King’s College London, Guy’s Campus, London SE1 1UL, United Kingdom Edited by Clifford J. Tabin, Harvard Medical School, Boston, MA, and approved November 11, 2014 (received for review May 28, 2014) The sternum bone lies at the ventral midline of the thorax where it Despite its critical role in tetrapod locomotion, the mecha- provides a critical attachment for the pectoral muscles that allow nisms controlling sternum development are not understood. In the forelimbs to raise the body from the ground. Among the mouse, the sternum is first visible as two condensing mes- tetrapods, sternum morphology is correlated with the mode of enchymal strips in the ventrolateral body wall at embryonic day locomotion: Avians that fly have a ventral extension, or keel, on (E) 12 (3). These bands move toward the midline and fuse to- their sterna, which provides an increased area for flight muscle gether, with the ribs attaching on either side. It was originally attachment. The sternum is fused with the ribs attaching on either proposed that the sternum is formed from the distal tips of the side; however, unlike the ribs, the sternal precursors do not ribs, which are somite-derived, but explant experiments demon- originate from the somites. Despite the crucial role of the sternum strated that the sternal precursors instead originate from the in tetrapod locomotion, little attention has been given to its lateral plate mesoderm (LPM) (1).
    [Show full text]
  • 8. Limb Development
    8. LIMB DEVELOPMENT Dr. Ann-Judith Silverman Department of Anatomy & Cell Biology Telephone: 212 305-3540 E-mail: [email protected] RECOMMENDED READING: Larsen’s Human Embryology, 3rd Edition, pages 315-328, 335-342 LEARNING OBJECTIVES: You should be able to: 1. Compare the contribution made by lateral plate (somatopleure) mesoderm and somitic (paraxial) mesoderm to the formation of the limb. 2. Follow the consequence of limb rotation on the innervation pattern of adult limbs. 3. Discuss the signaling mechanisms between the zone of polarizing activity and the apical ectodermal ridge in the anterior-posterior patterning of hand. 4. Describe the novel biochemistry whereby sonic hedgehog establishes a concentration gradient in the limb. GLOSSARY: Apical ectodermal ridge (AER) - most distal rim of epithelium of the limb bud. It is a major signalling center in regulating patterning of the limb and apoptosis in underlying mesoderm (see lecture on Apoptosis). Fibroblast growth factor (FGF) - FGF-4, a secreted protein from the AER overlying the ZPA, regu- lates the expression of SHH. Induction: the change in a cell or tissue’s fate due to a signal from another tissue or cell. Morphogen: A secreted molecule that regulates induction. A concentration gradient of the molecule is frequently established. Progress Zone (PZ) - mesoderm below AER where cellular proliferation takes place. Sonic hedgehog (SHH)- a member of the “hedgehog family” of secreted signalling proteins. SHH is made by the ZPA (below) and regulates anterior/poterior patterning. Zone of Polarizing Activity (ZPA) - mesenchyme just below the AER on the posterior boundary of the limb bud. Major signalling center for the regulation of anterior/posterior patterning.
    [Show full text]
  • Determining the Role of Wnt5a Signaling in Embryonic Limb Outgrowth Via Clonal Analysis
    Brigham Young University BYU ScholarsArchive Theses and Dissertations 2008-08-14 Determining the Role of Wnt5a Signaling in Embryonic Limb Outgrowth via Clonal Analysis Whitney Herrod Sowby Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd Part of the Cell and Developmental Biology Commons, and the Physiology Commons BYU ScholarsArchive Citation Sowby, Whitney Herrod, "Determining the Role of Wnt5a Signaling in Embryonic Limb Outgrowth via Clonal Analysis" (2008). Theses and Dissertations. 1638. https://scholarsarchive.byu.edu/etd/1638 This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. DETERMINING THE ROLE OF WNT5A IN EMBRYONIC LIMB OUTGROWTH VIA CLONAL ANALYSIS by Whitney Herrod Sowby A thesis submitted to the faculty of Brigham Young University in partial fulfillment of the requirements for the degree of Master of Science Department of Physiology and Developmental Biology Brigham Young University December 2008 Copyright © 2008 Whitney Herrod Sowby All Rights Reserved BRIGHAM YOUNG UNIVERSITY GRADUATE COMMITTEE APPROVAL of a thesis submitted by Whitney Herrod Sowby This thesis has been read by each member of the following graduate committee and by majority vote has been found to be satisfactory. Date Jeffery R. Barrow, Chair Date Michael R. Stark Date Laura C. Bridgewater BRIGHAM YOUNG UNIVERSITY As chair of the candidate’s graduate committee, I have read the thesis of Whitney Herrod Sowby in its final form and have found that (1) its format, citations, and bibliographical style are consistent and acceptable and fulfill university and department style requirements; (2) its illustrative materials including figures, tables, and charts are in place; and (3) the final manuscript is satisfactory to the graduate committee and is ready for submission to the university library.
    [Show full text]