DOCSLIB.ORG

FGF7 and FGF10 Directly Induce the Apical Ectodermal Ridge in Chick

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
FGF7 and FGF10 Directly Induce the Apical Ectodermal Ridge in Chick Developmental Biology 211, 133–143 (1999) Article ID dbio.1999.9290, available online at http://www.idealibrary.com on View metadata, citation and similar papers at core.ac.uk brought to you by CORE FGF7 and FGF10 Directly Induce the Apical provided by Elsevier - Publisher Connector Ectodermal Ridge in Chick Embryos Sayuri Yonei-Tamura,*,† Tetsuya Endo,* Hiroshi Yajima,* Hideyo Ohuchi,‡ Hiroyuki Ide,* and Koji Tamura*,†,1 *Biological Institute, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan; †Gene Expression Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037-1099; and ‡Department of Genetic Biochemistry, Faculty of Pharmaceutical Sciences, Kyoto University Graduate School of Pharmaceutical Sciences, Kyoto 606-8501, Japan During vertebrate limb development, the apical ectodermal ridge (AER) plays a vital role in both limb initiation and distal outgrowth of the limb bud. In the early chick embryo the prelimb bud mesoderm induces the AER in the overlying ectoderm. However, the direct inducer of the AER remains unknown. Here we report that FGF7 and FGF10, members of the fibroblast growth factor family, are the best candidates for the direct inducer of the AER. FGF7 induces an ectopic AER in the flank ectoderm of the chick embryo in a different manner from FGF1, -2, and -4 and activates the expression of Fgf8, an AER marker gene, in a cultured flank ectoderm without the mesoderm. Remarkably, FGF7 and FGF10 applied in the back induced an ectopic AER in the dorsal median ectoderm. Our results suggest that FGF7 and FGF10 directly induce the AER in the ectoderm both of the flank and of the dorsal midline and that these two regions have the competence for AER induction. Formation of the AER of the dorsal median ectoderm in the chick embryo is likely to appear as a vestige of the dorsal fin of the ancestors. © 1999 Academic Press Key Words: apical ectodermal ridge (AER); FGF7; FGF10; limb morphogenesis. INTRODUCTION developing limb bud (Saunders, 1948; Saunders et al., 1976), while mesenchymal factor(s) are responsible for maintain- Tetrapod limbs evolved from paired fins (pectoral and ing the AER as limb outgrowth proceeds (Zwilling and pelvic fins) of fish and appear to inherit embryonic devel- Hansborough, 1956). opment from fins (Akimenko et al., 1995; Akimenko and These interactions between the AER and limb mesen- Ekker, 1995). For example, a common specialized ectoderm, chyme are fundamental to the pattern formation of the which is required for skeletogenesis of the appendage, limb bud. Some molecules involved in these epithelial– appears in the distal margin of the limb and fin primordia mesenchymal tissue interactions have been reported. (Hall, 1991). One such structure is in the tetrapod limb bud Fibroblast growth factor (FGF) family members FGF2, -4, which appears as a ridge-shaped thickening in the apical and -8 have been reported to be the best candidates for the epidermis known as the apical ectodermal ridge (AER). In AER-derived signal since their transcripts are expressed the early limb bud stages, the AER is induced by the lateral in the AER, thus replacing the role of the AER (Fallon et plate mesoderm of the limb field (Saunders and Reuss, 1974; al., 1994; Niswander et al., 1994; Laufer et al., 1994; Carrington and Fallon, 1984). Experiments using avian Mahmood et al., 1995; Vogel et al., 1996). Exogenous embryos have revealed that the AER promotes proliferation insulin and insulin-like growth factor I (IGF-I) maintain and directed outgrowth of subridge mesodermal cells of the the thickness and activity of the AER (Dealy and Kosher, 1995) and, therefore, are candidates for the AER mainte- 1 To whom correspondence should be addressed at Biologi- nance factor. Moreover, recent studies showed that cal Institute, Graduate School of Science, Tohoku Univer- FGF10 is expressed in the limb mesenchyme and sug- sity, Sendai 980-8578, Japan. Fax: (022)-217-6691. E-mail: gested a role of FGF8 and FGF10 in the reciprocal [email protected]. interaction between the AER and limb mesenchyme 0012-1606/99 $30.00 Copyright © 1999 by Academic Press All rights of reproduction in any form reserved. 133 134 Yonei-Tamura et al. (Ohuchi et al., 1997; Xu et al., 1998). On the other hand, Observation of Skeletal Pattern although it is known that applications of several FGFs (FGF1, -2, -4, -8, and -10) to the flank can induce an For skeletal pattern observation, embryos were incubated for 7 additional limb bud with an ectopic AER (Cohn et al., days after operation. Embryos were fixed in 10% formalin, stained 1995; Crossley et al., 1996; Vogel et al., 1996; Ohuchi et in 0.1% Alcian blue in 70% acid alcohol, dehydrated in ethanol, and then cleared in methyl salicylate. al., 1997), there is little evidence about the direct inducer of the AER derived from the presumptive limb bud mesenchyme. In the present study, in order to identify the direct Whole-Mount in Situ Hybridization and inducer of the AER, we investigated the role of several FGFs Immunofluorescent Staining in AER induction. Particularly, we focused on FGF7 and FGF10. FGF7 is known as a diffusible mesenchymal media- Whole-mount in situ hybridization was performed as described (Yonei et al., 1995, for chick embryos; Endo et al., 1997, for tor of epithelial–mesenchymal tissue interactions in several Xenopus embryos; Schulte-Merker et al., 1992, for zebrafish em- organs (Rubin et al., 1995; Post et al., 1996). FGF10, which bryos). Antisense RNA probes for chick Fgf8 (a kind gift from Dr. is expressed in the presumptive limb mesenchyme, is Sumihare Noji) and Msx1 and Msx2 (gifts from Dr. Tsutomu thought to be most similar to FGF7 in both amino acid Nohno) were described previously (Yonei et al., 1995; Hara et al., sequence and functions (Yamasaki et al., 1996; Ohuchi et 1997; Ohuchi et al., 1997). Probes for zebrafish Fgf8 and Xenopus al., 1997; Igarashi et al., 1998). Our results demonstrate that Msx2 were synthesized from plasmids containing an 800-bp frag- FGF7 induces the AER in the flank in a different manner ment of zebrafish Fgf8 (Furthauer et al., 1997) and a 447-bp from FGF1, -2, and -4 and that FGF7 and FGF10 can induce fragment of Xenopus Msx2 (Su et al., 1991). After in situ hybrid- the formation of an additional AER in the ectoderm of the ization, some chick embryos were processed for embedding in OCT m dorsal midline where there is no underlying cell of lateral compound (Miles) and sectioned (10 m). For observation of the mesoderm. FGF7 can activate the expression of Fgf8 in the neural crest cells, frozen sections were immunostained using HNK-1 monoclonal antibody (Becton–Dickinson). ectoderm isolated from the underlying mesoderm in vitro but FGF1, -2, and -4 cannot. Thus, it is likely that FGF7 and FGF10 induce the AER directly while AER induction by FGF1, -2, and -4 may be mediated by mesodermal cells. Our Culture of Flank Ectoderm data also suggest that there may be a correlation between the dorsal median AER induced by FGF7 and FGF10 and the The procedure for ectoderm culture is described in the legend to Fig. 2A. Flank ectoderm was cultured using the floating collagen dorsal median fin in amphibian and fish larva. gel culture method (Emerman et al., 1977). The flank ectoderm including the lateral plate/paraxial mesoderm was dissected from stage 16 chick embryos. The ectoderm was isolated from the mesoderm using 0.5% trypsin in Tyrode at 4°C. Culture dishes MATERIALS AND METHODS were coated with collagen gel according to the accompanying procedure of Cellmatrix I-A (Nitta Gelatin). Explants were placed on collagen gel in Dulbecco’s modified Eagle’s MEM containing Experimental Manipulation 10% FCS, 10 mg/ml insulin, and 5 mg/ml transferrin. The media level was lowered until a thin layer of the ectoderm covered the gel. Chick embryos were staged according to Hamburger and Ham- Two hours after incubation at 37°C in the presence of 5% CO2, ilton (1951). Stage 13/14 chick embryos were used as hosts. The collagen gel was allowed to float in fresh medium and then ectoderm at somite 20 level was cut and partially peeled to be cultured with 10 ng/ml of FGF1, -2, -4, or -7 for 22 h (24 h in total). separated from a mesodermal layer toward somite 23/24 level in the flank. Affi-gel heparin beads (Bio-Rad) soaked in 0.5 mg/ml of several FGFs as described below were inserted in the cavity and placed between the respective regions of the ectoderm and meso- RT-PCR Analysis derm. FGF1 (recombinant human, Boehringer-Mannheim), FGF2 (bovine,R&DSystem), FGF4 (recombinant human,R&D Total RNA was isolated from explants using an RNeasy total System), and FGF7 (recombinant human, Promega) were used for RNA kit (Qiagen). RT-PCR was performed with Fgf8 specific this experiment. This operation was performed with meticulous primers (forward primer, 59-GAT GTG CAC GCC AAG CTC ATC care to prevent making a scrape on the ectoderm around the bead. GTC GAG ACC-39; reverse primer, 59-GCT TCA TGA AGT GCA When grafting the presumptive limb bud mesoderm of stage 16 CCT CGC GTT GGT GCT-39) and bactin specific primers (forward chick embryos, the transplants were isolated using 0.5% trypsin in primer, 59-TCT GAC TGA CCG CGT TAC TC-39; reverse primer, Tyrode at 4°C and inserted in the back using the same procedure as 59-CCA TCA CAC CCT GAT GTC TG-39). These primer sets were bead application (Fig. 4A). For retroviral infection, RCASBP(A) based on the chick Fgf8 mRNA sequence (GenBank No.
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]
  • Masking Techniques
    Available online at www.sciencedirect.com SCI ENCE(C$ DIRECT Developmental Biology 273 (2004) 361-372 www.elsevier.com/locate/ydbio The roles of Fgf4 and Fgf8 in limb bud initiation and outgrowth Anne M. Bouleta, Anne M. Moonb,c, Benjamin R. Arenkiela, Mario R. Capecchi3’* ^Department of Human Genetics, Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT 84112, USA bProgram in Human Molecular Biology and Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA cDepartment of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA Received for publication 12 May 2004, revised 16 June 2004, accepted 21 June 2004 Abstract Although numerous molecules required for limb bud formation have recently been identified, the molecular pathways that initiate this process and ensure that limb formation occurs at specific axial positions have yet to be fully elucidated. Based on experiments in the chick, Fg/8 expression in the intermediate mesoderm (IM) has been proposed to play a critical role in the initiation of limb bud outgrowth via restriction of Fgfl 0 expression to the appropriate region of the lateral plate mesoderm. Contrary to the outcome predicted by this model, ablation of Fgf8 expression in the intermediate mesoderm before limb bud initiation had no effect on initial limb bud outgrowth or on the formation of normal limbs. When their expression patterns were first elucidated, both Fgf4 and Fg/8 were proposed to mediate critical functions of the apical ectodermal ridge (AER), which is required for proper limb bud outgrowth.
    [Show full text]
  • ARTICLES Fibroblast Growth Factors 1, 2, 17, and 19 Are The
    0031-3998/07/6103-0267 PEDIATRIC RESEARCH Vol. 61, No. 3, 2007 Copyright © 2007 International Pediatric Research Foundation, Inc. Printed in U.S.A. ARTICLES Fibroblast Growth Factors 1, 2, 17, and 19 Are the Predominant FGF Ligands Expressed in Human Fetal Growth Plate Cartilage PAVEL KREJCI, DEBORAH KRAKOW, PERTCHOUI B. MEKIKIAN, AND WILLIAM R. WILCOX Medical Genetics Institute [P.K., D.K., P.B.M., W.R.W.], Cedars-Sinai Medical Center, Los Angeles, California 90048; Department of Obstetrics and Gynecology [D.K.] and Department of Pediatrics [W.R.W.], UCLA School of Medicine, Los Angeles, California 90095 ABSTRACT: Fibroblast growth factors (FGF) regulate bone growth, (G380R) or TD (K650E) mutations (4–6). When expressed at but their expression in human cartilage is unclear. Here, we deter- physiologic levels, FGFR3-G380R required, like its wild-type mined the expression of entire FGF family in human fetal growth counterpart, ligand for activation (7). Similarly, in vitro cul- plate cartilage. Using reverse transcriptase PCR, the transcripts for tivated human TD chondrocytes as well as chondrocytes FGF1, 2, 5, 8–14, 16–19, and 21 were found. However, only FGF1, isolated from Fgfr3-K644M mice had an identical time course 2, 17, and 19 were detectable at the protein level. By immunohisto- of Fgfr3 activation compared with wild-type chondrocytes and chemistry, FGF17 and 19 were uniformly expressed within the showed no receptor activation in the absence of ligand (8,9). growth plate. In contrast, FGF1 was found only in proliferating and hypertrophic chondrocytes whereas FGF2 localized predominantly to Despite the importance of the FGF ligand for activation of the resting and proliferating cartilage.
    [Show full text]
  • Development of the Endochondral Skeleton
    Downloaded from http://cshperspectives.cshlp.org/ on September 24, 2021 - Published by Cold Spring Harbor Laboratory Press Development of the Endochondral Skeleton Fanxin Long1,2 and David M. Ornitz2 1Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110 2Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri 63110 Correspondence: fl[email protected] SUMMARY Much of the mammalian skeleton is composed of bones that originate from cartilage templates through endochondral ossification. Elucidating the mechanisms that control endochondral bone development is critical for understanding human skeletal diseases, injury response, and aging. Mouse genetic studies in the past 15 years have provided unprecedented insights about molecules regulating chondrocyte formation, chondrocyte maturation, and osteoblast differ- entiation, all key processes of endochondral bone development. These include the roles of the secreted proteins IHH, PTHrP, BMPs, WNTs, and FGFs, their receptors, and transcription factors such as SOX9, RUNX2, and OSX, in regulating chondrocyte and osteoblast biology. This review aims to integrate the known functions of extracellular signals and transcription factors that regulate development of the endochondral skeleton. Outline 1 Introduction 5 Osteoblastogenesis 2 Mesenchymal condensation 6 Closing remarks 3 Chondrocyte differentiation References 4 Growth plate development Editors: Patrick P.L. Tam, W. James Nelson, and Janet Rossant Additional Perspectives on Mammalian Development available at www.cshperspectives.org Copyright # 2013 Cold Spring Harbor Laboratory Press; all rights reserved; doi: 10.1101/cshperspect.a008334 Cite this article as Cold Spring Harb Perspect Biol 2013;5:a008334 1 Downloaded from http://cshperspectives.cshlp.org/ on September 24, 2021 - Published by Cold Spring Harbor Laboratory Press F.
    [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]
  • A Frog Embryo with No Apical Ectodermal Ridge (AER)
    J. Anat. (1998) 192, pp. 379–390, with 6 figures Printed in the United Kingdom 379 Limb development and evolution: a frog embryo with no apical ectodermal ridge (AER) MICHAEL K. RICHARDSON1, TIMOTHY F. CARL2, JAMES HANKEN2, RICHARD P. ELINSON3, CELIA COPE1 AND PETER BAGLEY1 " # Department of Anatomy, St George’s Hospital Medical School, London, UK, Department of Environmental, Population, $ and Organismic Biology, University of Colorado, Boulder, CO, USA, and Department of Zoology, University of Toronto, Toronto, Ontario, Canada (Accepted 27 January 1998) The treefrog Eleutherodactylus coqui is a direct developer—it has no tadpole stage. The limb buds develop earlier than in metamorphosing species (indirect developers, such as Xenopus laevis). Previous molecular studies suggest that at least some mechanisms of limb development in E. coqui are similar to those of other vertebrates and we wished to see how limb morphogenesis in this species compares with that in other vertebrates. We found that the hind limb buds are larger and more advanced than the forelimbs at all stages examined, thus differing from the typical amniote pattern. The limb buds were also small compared to those in the chick. Scanning and transmission electron microscopy showed that although the apical ectoderm is thickened, there was no apical ectodermal ridge (AER). In addition, the limb buds lacked the dorsoventral flattening seen in many amniotes. These findings could suggest a mechanical function for the AER in maintaining dorsoventral flattening, although not all data are consistent with this view. Removal of distal ectoderm from E. coqui hindlimb buds does not stop outgrowth, although it does produce anterior defects in the skeletal pattern.
    [Show full text]
  • Sonic Hedgehog Signaling in Limb Development
    REVIEW published: 28 February 2017 doi: 10.3389/fcell.2017.00014 Sonic Hedgehog Signaling in Limb Development Cheryll Tickle 1* and Matthew Towers 2* 1 Department of Biology and Biochemistry, University of Bath, Bath, UK, 2 Department of Biomedical Science, The Bateson Centre, University of Sheffield, Western Bank, Sheffield, UK The gene encoding the secreted protein Sonic hedgehog (Shh) is expressed in the polarizing region (or zone of polarizing activity), a small group of mesenchyme cells at the posterior margin of the vertebrate limb bud. Detailed analyses have revealed that Shh has the properties of the long sought after polarizing region morphogen that specifies positional values across the antero-posterior axis (e.g., thumb to little finger axis) of the limb. Shh has also been shown to control the width of the limb bud by stimulating mesenchyme cell proliferation and by regulating the antero-posterior length of the apical ectodermal ridge, the signaling region required for limb bud outgrowth and the laying down of structures along the proximo-distal axis (e.g., shoulder to digits axis) of the limb. It has been shown that Shh signaling can specify antero-posterior positional values in Edited by: limb buds in both a concentration- (paracrine) and time-dependent (autocrine) fashion. Andrea Erika Münsterberg, University of East Anglia, UK Currently there are several models for how Shh specifies positional values over time in the Reviewed by: limb buds of chick and mouse embryos and how this is integrated with growth. Extensive Megan Davey, work has elucidated downstream transcriptional targets of Shh signaling. Nevertheless, it University of Edinburgh, UK Robert Hill, remains unclear how antero-posterior positional values are encoded and then interpreted University of Edinburgh, UK to give the particular structure appropriate to that position, for example, the type of digit.
    [Show full text]
  • Of Limb Morphogenesis in a Model System
    DEVELOPMENTAL BIOLOGY 28, 113-122 (1972) Analysis of Limb Morphogenesis in a Model System ROBERT H. SINGER’. 2 Department of Biology, Brandeis University, Waltham, Massachusetts Accepted January 27, 1972 A method for analysis of chicken limb morphogenesis was devised. This method consisted of grafting a limb ectodermal jacket containing dissociated and pelleted mesenchymal cellular com- ponents to the host somites. Different cellular components stuffed into the ectoderm could be mixed in varied ratios. After 7 days the grafts were analyzed for outgrowth. Stage 19 mesoblast cells alone when treated as above gave limblike outgrowths with good digits, toes, and claws in all cases. However, mesoblasts from the proximal half of older limbs (stages 24, 25 and chondro- cytes) gave no outgrowths, and those from stage 23 gave outgrowths in 9% of the cases. In mixtures of 5% stage 19 cells with 95% chondrocytes, consistent morphogenesis (i.e., in 65% of grafts) oc- curred. The amount of morphogenesis (size of graft and perfection of digits) was directly propor- tional to the amount of stage 19 cells. However, these cells mixed with proximal cells of stages 23, 24, or 25 required higher proportions for equivalent morphogenesis. To obtain morphogenesis equivalent to the 5% mixture with chondrocytes, 10% stage 19 cells were needed when mixed with proximal stage 23, 25% with proximal stage 24 and 7% with proximal stage 25. Mixtures of stage 19 cells added to nonlimb (flank, stage- 19) mesoderm, formed large tumorous mounds of tissue with no limblike features. INTRODUCTION ectoderm ridge serves as a specific induc- The limb bud presents a good model of tive structure initiating and directing out- a developing system.
    [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]
  • FGF Signaling Network in the Gastrointestinal Tract (Review)
    163-168 1/6/06 16:12 Page 163 INTERNATIONAL JOURNAL OF ONCOLOGY 29: 163-168, 2006 163 FGF signaling network in the gastrointestinal tract (Review) MASUKO KATOH1 and MASARU KATOH2 1M&M Medical BioInformatics, Hongo 113-0033; 2Genetics and Cell Biology Section, National Cancer Center Research Institute, Tokyo 104-0045, Japan Received March 29, 2006; Accepted May 2, 2006 Abstract. Fibroblast growth factor (FGF) signals are trans- Contents duced through FGF receptors (FGFRs) and FRS2/FRS3- SHP2 (PTPN11)-GRB2 docking protein complex to SOS- 1. Introduction RAS-RAF-MAPKK-MAPK signaling cascade and GAB1/ 2. FGF family GAB2-PI3K-PDK-AKT/aPKC signaling cascade. The RAS~ 3. Regulation of FGF signaling by WNT MAPK signaling cascade is implicated in cell growth and 4. FGF signaling network in the stomach differentiation, the PI3K~AKT signaling cascade in cell 5. FGF signaling network in the colon survival and cell fate determination, and the PI3K~aPKC 6. Clinical application of FGF signaling cascade in cell polarity control. FGF18, FGF20 and 7. Clinical application of FGF signaling inhibitors SPRY4 are potent targets of the canonical WNT signaling 8. Perspectives pathway in the gastrointestinal tract. SPRY4 is the FGF signaling inhibitor functioning as negative feedback apparatus for the WNT/FGF-dependent epithelial proliferation. 1. Introduction Recombinant FGF7 and FGF20 proteins are applicable for treatment of chemotherapy/radiation-induced mucosal injury, Fibroblast growth factor (FGF) family proteins play key roles while recombinant FGF2 protein and FGF4 expression vector in growth and survival of stem cells during embryogenesis, are applicable for therapeutic angiogenesis. Helicobacter tissues regeneration, and carcinogenesis (1-4).
    [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]