401
|
Affiliation(s)
- B L Hogan
- Howard Hughes Institute and Department of Cell Biology, Vanderbilt University Medical School, Nashville, Tennessee 37232-2175, USA
| |
Collapse
|
402
|
Zhao GQ, Hogan BL. Evidence that mouse Bmp8a (Op2) and Bmp8b are duplicated genes that play a role in spermatogenesis and placental development. Mech Dev 1996; 57:159-68. [PMID: 8843393 DOI: 10.1016/0925-4773(96)00543-6] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We have identified two highly conserved mouse genes encoding bone morphogenetic protein 8A (BMP8A/OP2) and 8B (BMP8B). The two loci are tightly linked on chromosome 4, suggesting that they arose through a recent gene duplication. Contrary to previous reports, neither gene is expressed in the early postimplantation mouse embryo (7.5-10.5 days post coitum) as judged by a variety of sensitive techniques. By contrast, high levels of Bmp8b RNA are found in the decidual cells of the uterus, and both genes are expressed in the trophoblast cells of the labyrinthine region of the placenta and in the inner root sheath of hair follicles of early postnatal skin. In addition, both Bmp8a and Bmp8b are expressed in the testis during specific stages of spermatogenesis, with the highest levels of RNA in stage 6-8 round spermatids after 3 weeks of age. Bmp8a and 8b are, therefore, the first members of the transforming growth factor beta (TGF beta)-related gene family to be found expressed in the germ cells of the testis, rather than in the somatic Sertoli cells. These results suggest that Bmp8a and 8b are not required for development of the embryo proper but regulate aspects of cell proliferation, survival and/or differentiation during spermatogenesis and placentation.
Collapse
Affiliation(s)
- G Q Zhao
- Howard Hughes Medical Institute, Vanderbilt University Medical School, Nashville, TN 37232-2175, USA
| | | |
Collapse
|
403
|
Constam DB, Calfon M, Robertson EJ. SPC4, SPC6, and the novel protease SPC7 are coexpressed with bone morphogenetic proteins at distinct sites during embryogenesis. J Biophys Biochem Cytol 1996; 134:181-91. [PMID: 8698813 PMCID: PMC2120924 DOI: 10.1083/jcb.134.1.181] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In the present study, we screened for subtilisin-like proprotein convertases (SPCs) that potentially regulate the activation of known growth factors during embryonic development. We isolated a novel protease, SPC7, as well as several known SPCs. SPC7, like SPC1, is expressed ubiquitously throughout development. In contrast, SPC4 and SPC6 exhibit dynamic expression patterns. SPC4 transcripts were initially detected in the granulosa cells of secondary follicles. Shortly after implantation, SPC4 transcripts are localized to extraembryonic cell populations, and at later stages are detected in discrete tissues including the primitive gut, heart, neural tube, and limb buds. Within the limb buds, SPC4 mRNA is most abundant in the apical ectodermal ridge (AER). At later stages of limb development, SPC4 mRNA is strongly expressed in cartilage and in the interdigital mesenchyme. In contrast, high SPC6 mRNA levels are detected in somites, the dorsal surface ectoderm, and in vertebral cartilage primordia. In limb buds, SPC6 is strongly expressed in the AER, and at later stages in dorsal mesenchyme. A comparison of these expression patterns with those of several bone morphogenetic proteins (BMPs) indicates that processing of these growth factors may be limited by the local availability of SPCs.
Collapse
Affiliation(s)
- D B Constam
- Harvard University, Department of Molecular and Cellular Biology, The Biological Laboratories, Cambridge, Massachusetts 02138, USA
| | | | | |
Collapse
|
404
|
Tiedemann H, Asashima M, Born J, Grunz H, Knochel W, Tiedemann H. Determination, induction and pattern formation in early amphibian embryos. Dev Growth Differ 1996. [DOI: 10.1046/j.1440-169x.1996.t01-2-00002.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
405
|
|
406
|
Lowe LA, Supp DM, Sampath K, Yokoyama T, Wright CV, Potter SS, Overbeek P, Kuehn MR. Conserved left-right asymmetry of nodal expression and alterations in murine situs inversus. Nature 1996; 381:158-61. [PMID: 8610013 DOI: 10.1038/381158a0] [Citation(s) in RCA: 366] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Vertebrates have characteristic and conserved left-right (L-R) visceral asymmetries, for example the left-sided heart. In humans, alterations of L-R development can have serious clinical implications, including cardiac defects. Although little is known about how the embryonic L-R axis is established, a recent study in the chick embryo revealed L-R asymmetric expression of several previously cloned genes, including Cnr-1 (for chicken nodal-related-1), and indicated how this L-R molecular asymmetry might be important for subsequent visceral morphogenesis. Here we show that nodal is asymmetrically expressed in mice at similar stages, as is Xnr-1 (for Xenopus nodal related-1) in frogs. We also examine nodal expression in two mouse mutations that perturb L-R development, namely situs inversus viscerum (iv), in which assignment of L-R asymmetry is apparently random and individuals develop either normally or are mirror-image-reversed (situs inversus), and inversion of embryonic turning (inv), in which all individuals develop with situs inversus. In both, nodal expression is strikingly affected, being reversed or converted to symmetry. These results further support a key role for nodal and nodal-related genes in interpreting and relaying L-R patterning information in vertebrates. To our knowledge, our results provide the first direct evidence that iv and inv normally function well before the appearance of morphological L-R asymmetry.
Collapse
Affiliation(s)
- L A Lowe
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | | | | | | | |
Collapse
|
407
|
Meno C, Saijoh Y, Fujii H, Ikeda M, Yokoyama T, Yokoyama M, Toyoda Y, Hamada H. Left-right asymmetric expression of the TGF beta-family member lefty in mouse embryos. Nature 1996; 381:151-5. [PMID: 8610011 DOI: 10.1038/381151a0] [Citation(s) in RCA: 324] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Examples of lateral asymmetry are often found in vertebrates, such as the heart being on the left side, but the molecular mechanism governing the establishment of this left-right (L-R) handedness is unknown. A diffusible morphogen may determine L-R polarity, but a likely molecule has not so far been identified. Here we report on the gene lefty, a member of the transforming growth factor-beta family, which may encode a morphogen for L-R determination. Lefty protein contains the cysteine-knot motif characteristic of this superfamily and is secreted as a processed form of relative molecular mass 25K-32K. Surprisingly, lefty is expressed in the left half of gastrulating mouse embryos. This asymmetric expression is very transient and occurs just before the first sign of lateral asymmetry appears. In the mouse mutants iv and inv, which cause situs inversus, the sites of lefty expression are inverted, indicating that lefty is downstream of iv and inv. These results suggest that lefty may be involved in setting up L-R asymmetry in the organ systems of mammals.
Collapse
Affiliation(s)
- C Meno
- Tokyo Metropolitan Institute of Medical Science, Japan
| | | | | | | | | | | | | | | |
Collapse
|
408
|
Collignon J, Varlet I, Robertson EJ. Relationship between asymmetric nodal expression and the direction of embryonic turning. Nature 1996; 381:155-8. [PMID: 8610012 DOI: 10.1038/381155a0] [Citation(s) in RCA: 440] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Growth factors related to TGF-beta provide important signals for patterning the vertebrate body plan. One such family member, nodal, is required for formation of the primitive streak during mouse gastrulation. Here we have used a nodal-lacZ reporter allele to demonstrate asymmetric nodal expression in the mouse node, a structure thought to be the functional equivalent of the frog and chick 'organizer', and in lateral place mesoderm cells. We have also identified two additional genes acting with nodal in a pathway determining the left-right body axis. Thus we observe in inv mutant embryos that the sidedness of nodal expression correlates with the direction of heart looping and embryonic turning. In contrast, HNF3-beta(+/-) nodal(lacZ/+) double-heterozygous embryos display LacZ staining on both left and right sides, and frequently exhibit defects in body situs. Taken together, these experiments, along with similar findings in chick, demonstrate that elements of the genetic pathway that establish the left-right body axis are conserved in vertebrates.
Collapse
Affiliation(s)
- J Collignon
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | | | | |
Collapse
|
409
|
Bellomo D, Lander A, Harragan I, Brown NA. Cell proliferation in mammalian gastrulation: the ventral node and notochord are relatively quiescent. Dev Dyn 1996; 205:471-85. [PMID: 8901057 DOI: 10.1002/(sici)1097-0177(199604)205:4<471::aid-aja10>3.0.co;2-4] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
During gastrulation, the node of the mammalian embryo appears to be an organising centre, homologous to Hensen's node in the chick and the dorsal lip of the amphibian blastopore. In addition, the node serves as a precursor population for the head process, notochord and foregut endoderm. We have studied node architecture and cell morphology by electron microscopy, and cell proliferation using bromodeoxyuridine incorporation and mitotic counts. The dorsal (ectodermal) and ventral (endodermal) components of the node are two distinct populations, separated by a basement membrane. The ventral node, contiguous with the head process, is characterised by a relatively low proliferation rate, with only approximately 10% of cells incorporating BrdU over 4 hr, compared to > 95% in surrounding mesodermal and ectodermal tissues. This is the case from the beginning of node formation, at the no-allantoic-bud stage, until the 7 somite stage, and is not compatible with the idea that the ventral node is a stem cell population. The dorsal node is highly proliferative, its rate of division being indistinguishable from the neurectoderm, with which it is contiguous. In the ventral node, two regions can be recognised: cells in the "pit" are columnar and all monociliated; around them lies a "crown" of cells arranged radially in a horseshoe shape and less often ciliated. Node derivatives share common features with the ventral node; the head process and the notochord are relatively quiescent; and some head process cells are also monociliated. Node and head process monocilia are immotile and appear to be associated with non-proliferation. We suggest that the ventral node contains all the properties of the organiser, while the dorsal node is indistinct from the surrounding epiblast. The cranial end of the foregut pouch, the thyroid diverticulum, and the promyocardium of early somite stage embryos are also areas of low cell division. All the described regions of relative quiescence are sites of expression of members of the TGF beta family, which may be involved in maintaining non-proliferation.
Collapse
Affiliation(s)
- D Bellomo
- Department of Child Health, St. George's Hospital Medical School, London, United Kingdom
| | | | | | | |
Collapse
|
410
|
Hishinuma M, Takahashi Y, Kanagawa H. Post-implantation development of demi-embryos and induction of decidual cell reaction in mice. Theriogenology 1996; 45:1187-200. [PMID: 16727875 DOI: 10.1016/0093-691x(96)00074-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/1995] [Accepted: 10/18/1995] [Indexed: 10/18/2022]
Abstract
Mouse demi-embryos that developed from bisected morulae were transferred to recipients. The eu-blastocysts (distinct inner cell mass and well-developed trophectoderm) contained cells equal to 51% of the controls that developed from zona-free morulae. The rate of decidual cell reaction induced by the eu-blastocysts was not significantly different from that of the controls, but the size of the deciduum containing the egg cylinder was significantly smaller on Day 5.5 of pregnancy (P < 0.001). A significant increase in embryonic loss was observed from Day 7.5 to Day 9.5 in the eu-blastocysts (P < 0.05), while the controls exhibited no significant difference. Although the embryos from the eu-blastocysts showed retardation of developmental stages and decreased size, they attained normal stages and size regulation up to 90% of that of the control on Day 10.5. The pseudo-blastocysts (poorly developed inner cell mass enclosed by trophectoderm) contained cells equal to 25% of those of the controls and showed less than a 10% developmental rate to the egg cylinder stage. The trophectodermal vesicles (no enclosed cells) and nonintegrated forms (disorganized clusters of cells) contained cells less than 18% of those of the controls. They showed lower rates of decidual cell reaction than those in the controls (P < 0.05), and no egg cylinder was found in the deciduum. The results indicate that a severe decrease in the number of embryonic cells affects the regulation of embryonic development and decidual cell reaction in the uterus.
Collapse
Affiliation(s)
- M Hishinuma
- Laboratory of Theriogenology, Department of Veterinary Clinical Science, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060, Japan
| | | | | |
Collapse
|
411
|
Nagy A, Rossant J. Targeted mutagenesis: analysis of phenotype without germ line transmission. J Clin Invest 1996; 97:1360-5. [PMID: 8617866 PMCID: PMC507193 DOI: 10.1172/jci118555] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The available techniques for directed gene manipulation in the mouse are unprecedented in any multicellular organism and make the mouse an invaluable tool for unraveling all aspects of mammalian biology. To realize fully the potential of these genetic tools requires that phenotypic analysis be efficient, rapid, and complete. Genetic chimeras and mosaics, in which mutant cells are mixed with wild-type cells, can be used to augment standard analysis of intact mutant animals and alleviate the time required and the expense involved in generating and maintaining multiple strains of mutant mice.
Collapse
Affiliation(s)
- A Nagy
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | | |
Collapse
|
412
|
Joore J, Fasciana C, Speksnijder JE, Kruijer W, Destrée OH, van den Eijnden-van Raaij AJ, de Laat SW, Zivkovic D. Regulation of the zebrafish goosecoid promoter by mesoderm inducing factors and Xwnt1. Mech Dev 1996; 55:3-18. [PMID: 8734495 DOI: 10.1016/0925-4773(95)00481-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Goosecoid is a homeobox gene that is expressed as an immediate early response to mesoderm induction by activin. We have investigated the induction of the zebrafish goosecoid promoter by the mesoderm inducing factors activin and basic fibroblast growth factor (bFGF) in dissociated zebrafish blastula cells, as well as by different wnts in intact embryos. Activin induces promoter activity, while bFGF shows a cooperative effect with activin. We have identified two enhancer elements that are functional in the induction of the goosecoid promoter. A distal element confers activin responsiveness to a heterologous promoter in the absence of de novo protein synthesis, whereas a proximal element responds only to a combination of activin and bFGF. Deletion experiments show that both elements are important for full induction by activin. Nuclear proteins that bind to these elements are expressed in blastula embryos, and competition experiments show that an octamer site in the activin responsive distal element is specifically bound, suggesting a role for an octamer binding factor in the regulation of goosecoid expression by activin. Experiments in intact embryos reveal that the proximal element contains sequences that respond to Xwnt1, but not to Xwnt5c. Furthermore, we show that the distal element is active in a confined dorsal domain in embryos and responds to overexpression of activin in vivo, as well as to dorsalization by lithium. The distal element is to our knowledge the first enhancer element identified that mediates the induction of a mesodermal gene by activin.
Collapse
Affiliation(s)
- J Joore
- Hubrecht Laboratory, Netherlands Institute for Developmental Biology, Utrecht, The Netherlands
| | | | | | | | | | | | | | | |
Collapse
|
413
|
Abstract
To investigate the inductive activities of the vertebrate organizer, we transplanted the chicken organizer (Hensen's node) into zebrafish gastrula and analyzed resulting secondary axes. Grafted Hensen's node did not differentiate or participate in the secondary axis. It also did not induce a secondary notochord or expression of the genes normally expressed by the fish organizer including no tail, axial, goosecoid. Nevertheless, it recruited fish cells to organize a variety of tissues: the dorsal portion of the central nervous system including Rohon-Beard sensory neurons, otic vesicles, dorsal pigment stripe, dorsal fin, somites, heart, and pronephric ducts. Enlarged neural plate induced by the organizer was shown by the expression pattern of dlx3 and msxB genes, which demarcates the early presumptive neural tissue. In addition, Hensen's node of an earlier stage chicken embryo displayed differential movement in zebrafish from that of a later stage. This might reflect unknown differences in properties between the organizer at two different developmental stages related to its normal organizer activity. To create a model system to study the molecular mechanisms of the organizer, we next transplanted genetically modified mouse cells into zebrafish embryos. We found that Wnt3A-transfected NIH3T3 cells are much more potent in inducing a secondary axis than NIH3T3 cells alone. These results suggest that formation of a variety of tissues are controlled by signalling from the organizer itself with no requirement of participation of the organizer-derived tissues. Additionally, the activities of the organizer may involve a function of Wnt-family genes.
Collapse
Affiliation(s)
- K Hatta
- Institute of Neuroscience, University of Oregon, Eugene 97403-1254, USA
| | | |
Collapse
|
414
|
Bachvarova RF. Anterior-Posterior Polarization and Mesoderm Inducing Factors in the Pregastrula Mouse Embryo: Comparison to Chick and Frog Embryos. ADVANCES IN DEVELOPMENTAL BIOLOGY (1992) 1996. [DOI: 10.1016/s1566-3116(08)60018-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
415
|
Hermesz E, Mackem S, Mahon KA. Rpx: a novel anterior-restricted homeobox gene progressively activated in the prechordal plate, anterior neural plate and Rathke's pouch of the mouse embryo. Development 1996; 122:41-52. [PMID: 8565852 DOI: 10.1242/dev.122.1.41] [Citation(s) in RCA: 162] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have isolated a new murine homeobox gene, Rpx (for Rathke's pouch homeobox), that is dynamically expressed in the prospective cephalic region of the embryo during gastrulation. Early expression is seen in the anterior midline endoderm and prechordal plate precursor. Expression is subsequently activated in the overlying ectoderm of the cephalic neural plate, suggesting that inductive contact with Rpx-expressing mesendoderm is required for this expression. Subsequently, Rpx expression is extinguished in the mesendoderm while remaining in the prospective prosencephalic region of the neural plate ectoderm. Ultimately, transcripts become restricted to Rathke's pouch, the primordium of the pituitary, which is known to be derived from the most anterior ectoderm of the early embryo. Down regulation of Rpx in the pouch coincides with the differentiation of pituitary-specific cell types. Rpx is the earliest known marker for the pituitary primordium, suggestive of a role in the early determination or differentiation of the pituitary. Since Rpx is expressed so dynamically and so early in the anterior region of the embryo, and since its early expression domain is much more extensive than the region fated to form the pituitary, it is likely that Rpx is involved in the initial determination of the anterior (prechordal) region of the embryo.
Collapse
Affiliation(s)
- E Hermesz
- Laboratory of Mammalian Genes and Development, NICHD, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | |
Collapse
|
416
|
The transforming growth factor β superfamily. GROWTH FACTORS AND CYTOKINES IN HEALTH AND DISEASE 1996. [DOI: 10.1016/s1874-5687(96)80016-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
417
|
Abstract
Identification of the signalling molecules involved in mesoderm formation in amphibian embryos still presents problems. None of the original candidates, such as activin, have been definitively ruled out, and new factors, such as the nodal-related genes, have come on to the scene. Of the original candidates, activin has been definitively shown to act as a morphogen, whereas bone morphogenetic protein (BMP)-4 has emerged as a ventral inducer and an inhibitor of neural differentiation. The effects of BMP-4 are antagonized by chordin, a molecule related to the product of the Drosophila gene short gastrulation.
Collapse
Affiliation(s)
- J C Smith
- Division of Developmental Biology, National Institute for Medical Research, London, UK.
| |
Collapse
|
418
|
Gaddy-Kurten D, Vale WW. Activin increases phosphorylation and decreases stability of the transcription factor Pit-1 in MtTW15 somatotrope cells. J Biol Chem 1995; 270:28733-9. [PMID: 7499395 DOI: 10.1074/jbc.270.48.28733] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Activin is a polypeptide growth factor which exerts endocrine, paracrine, and autocrine effects in a variety of tissues. In the pituitary somatotrope, activin represses proliferation and growth hormone (GH) biosynthesis and secretion. We previously demonstrated that decreases in GH biosynthesis in MtTW15 somatotrope cells are due at least in part to decreased binding of the tissue-specific transcription factor, Pit-1, to the GH promoter, resulting in decreased transcription of the GH gene. The objective of the current study was to determine the extent to which activin-mediated decreases in GH transcription were the result of decreased Pit-1 activity and/or decreased Pit-1 protein content in MtTW15 cells. Activin caused rapid increases in Pit-1 phosphorylation, which were temporally correlated with decreases in GH DNA binding. Pit-1 phosphorylation preceded marked decreases in steady-state levels of Pit-1 protein. The rate of Pit-1 synthesis was only moderately decreased by activin, with a time-course similar to that observed for decreases in GH biosynthesis. However, Pit-1 stability was markedly decreased after more than 4 h of activin treatment. These data demonstrate that activin decreases GH expression in MtTW15 cells through multilevel regulation of Pit-1, which may represent a more general mechanism whereby activin and other transforming growth factor beta family members modulate gene expression through regulation of transcription factor activity as well as content.
Collapse
Affiliation(s)
- D Gaddy-Kurten
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute, La Jolla, California 92037-1099, USA
| | | |
Collapse
|
419
|
Dudley AT, Lyons KM, Robertson EJ. A requirement for bone morphogenetic protein-7 during development of the mammalian kidney and eye. Genes Dev 1995; 9:2795-807. [PMID: 7590254 DOI: 10.1101/gad.9.22.2795] [Citation(s) in RCA: 812] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BMP-7/OP-1, a member of the transforming growth factor-beta (TGF-beta) family of secreted growth factors, is expressed during mouse embryogenesis in a pattern suggesting potential roles in a variety of inductive tissue interactions. The present study demonstrates that mice lacking BMP-7 display severe defects confined to the developing kidney and eye. Surprisingly, the early inductive tissue interactions responsible for establishing both organs appear largely unaffected. However, the absence of BMP-7 disrupts the subsequent cellular interactions required for their continued growth and development. Consequently, homozygous mutant animals exhibit renal dysplasia and anophthalmia at birth. Overall, these findings identify BMP-7 as an essential signaling molecule during mammalian kidney and eye development.
Collapse
Affiliation(s)
- A T Dudley
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | | | | |
Collapse
|
420
|
Williams R, Lendahl U, Lardelli M. Complementary and combinatorial patterns of Notch gene family expression during early mouse development. Mech Dev 1995; 53:357-68. [PMID: 8645602 DOI: 10.1016/0925-4773(95)00451-3] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The Drosophila Notch gene encodes a transmembrane receptor involved in the regulation of cell fate. It exerts its effect by lateral specification, inductive signaling and is also important for cell adhesion and axonal pathfinding. In this report we analyse the expression of the three mammalian Notch homologues during early mouse development by in situ hybridization. The Notch 1, 2 and 3 genes show dynamic and complex expression patterns, in particular during gastrulation and somitogenesis and in early nervous system formation. During gastrulation, the Notch genes are expressed in non-overlapping, successive patterns. Notch 3 is widely expressed in both ectoderm and mesoderm. Notch 2 is then expressed in the node, notochord and neural groove while Notch 1 becomes highly expressed in presomitic mesoderm. As somitogenesis begins, Notch 2 expression is activated in newly forming somites while Notch 3 is activated in mature somites. Various neural crest cell populations and ectodermal placode cells can be defined by expression of specific combinations of Notch genes. All three Notch genes are expressed within cells of the dorsal neural tube at E9.5, although neural crest cells that have begun migrating all show distinct patterns of Notch expression. Finally, Notch 1 expression is observed not only in placodes, but also in cells migrating from placodes to the site of the ganglia anlagen. This expression pattern may be analogous to Notch expression in the peripheral nervous system of Drosophila, suggesting that mammalian Notch genes may also be involved in axonal pathfinding.
Collapse
Affiliation(s)
- R Williams
- Department of Cell and Molecular Biology, Medical Nobel Institute, Karolinska Institute, Stockholm, Sweden
| | | | | |
Collapse
|
421
|
Jones CM, Kuehn MR, Hogan BL, Smith JC, Wright CV. Nodal-related signals induce axial mesoderm and dorsalize mesoderm during gastrulation. Development 1995; 121:3651-62. [PMID: 8582278 DOI: 10.1242/dev.121.11.3651] [Citation(s) in RCA: 290] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mouse embryos homozygous for a null mutation in nodal arrest development at early gastrulation and contain little or no embryonic mesoderm. Here, two Xenopus nodal-related genes (Xnr-1 and Xnr-2) are identified and shown to be expressed transiently during embryogenesis, first within the vegetal region of late blastulae and later in the marginal zone during gastrulation, with enrichment in the dorsal lip. Xnrs and mouse nodal function as dose-dependent dorsoanterior and ventral mesoderm inducers in whole embryos and explanted animal caps. Using a plasmid vector to produce Xnr proteins during gastrulation, we show that, in contrast to activin and other TGF beta-like molecules, Xnr-1 and Xnr-2 can dorsalize ventral marginal zone explants and induce muscle differentiation. Xnr signalling also rescues a complete embryonic axis in UV-ventralized embryos. The patterns of Xnr expression, the activities of the proteins and the phenotype of mouse nodal mutants, all argue strongly that a signaling pathway involving nodal, or nodal-related peptides, is an essential conserved element in mesoderm differentiation associated with vertebrate gastrulation and axial patterning.
Collapse
Affiliation(s)
- C M Jones
- Department of Cell Biology, Vanderbilt University Medical School, Nashville, TN 37232-2175, USA
| | | | | | | | | |
Collapse
|
422
|
Reddi AH. Cartilage morphogenesis: role of bone and cartilage morphogenetic proteins, homeobox genes and extracellular matrix. Matrix Biol 1995; 14:599-606. [PMID: 9057810 DOI: 10.1016/s0945-053x(05)80024-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Cartilage morphogenesis is one of the central topics in skeletal development. Cartilage geometry determines the future architecture of bones, joints and associated ligaments and tendons. Recent progress in this area has come from purification, cloning and expression of genes encoding bone and cartilage morphogenetic proteins (BMPs and CDMPs). BMPs initiate de novo cartilage and bone differentiation. BMPs are a family of pleiotropic signals for progenitor cell migration by chemotaxis, proliferation, and differentiation. Very recently another class of related morphogenetic proteins, CDMPs have been isolated and cloned. CDMPs may be critical for mesenchymal condensation prior to overt cartilage differentiation, the first step in morphogenesis of both cartilage and bone. The cartilage morphogenetic cascade is a cellular and molecular continuum driven by regulatory signalling molecules such as BMPs and CDMPs and their receptors, homeobox genes, transcription factors, and finally the synthesis and supramolecular assembly of structural macromolecules of the extracellular matrix. BMPs and CDMPs bind to heparin, heparan sulfates, and collagens I and IV. Thus there is a symbiosis of regulatory and structural macromolecules in the morphogenesis of cartilage. An avalanche of recent advances from seemingly disparate areas bodes well for the complete elucidation of the molecular basis of morphogenesis of cartilage, the architectural blue-print for the skeleton.
Collapse
Affiliation(s)
- A H Reddi
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
423
|
Abstract
Recent advances in our understanding of axis formation and patterning in zebrafish relate the developmental mode of this aspiring genetic model organism to higher vertebrates. The effect of UV irradiation and lithium treatment, as well as detailed early lineage analyses, have shed some light on dorsoventral axis formation. However, the molecular mechanism of axis formation, as well as the identity of a fish Nieuwkoop center, are still open issues. A Vg1 homolog is expressed in zebrafish, and activin as well as the mouse nodal gene product have been demonstrated to induce mesoderm and ectopic axes, respectively, in zebrafish. The zebrafish organizer is defined by the expression domains of goosecoid, axial, and lim1. The cyclops gene is involved in maintaining goosecoid expression in axial mesoderm of the head. Large mutagenesis screens provide the basis for a genetic analysis of axis formation.
Collapse
Affiliation(s)
- W Driever
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown 02129-2060, USA
| |
Collapse
|
424
|
Kruijssen CMM, Achterberg TAE, Feijen A, Hebert JM, Waele P, Eijnden-van Raaij AJM. Neuronal and mesodermal differentiation of P19 embryonal carcinoma cells is characterized by expression of specific marker genes and modulated by activin and fibroblast growth factors. Dev Growth Differ 1995. [DOI: 10.1046/j.1440-169x.1995.t01-3-00011.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
425
|
Levin M, Johnson RL, Stern CD, Kuehn M, Tabin C. A molecular pathway determining left-right asymmetry in chick embryogenesis. Cell 1995; 82:803-14. [PMID: 7671308 DOI: 10.1016/0092-8674(95)90477-8] [Citation(s) in RCA: 576] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
While significant progress has been made in understanding the molecular events underlying the early specification of the antero-posterior and dorso-ventral axes, little information is available regarding the cellular or molecular basis for left-right (LR) differences in animal morphogenesis. We describe the expression patterns of three genes involved in LR determination in chick embryos: activin receptor IIa, Sonic hedgehog (Shh), and cNR-1 (related to the mouse gene nodal). These genes are expressed asymmetrically during and after gastrulation and regulate the expression of one another in a sequential pathway. Moreover, manipulation of the sidedness of either activin protein or Shh expression alters heart situs. Together, these observations identify a cascade of molecular asymmetry in that determines morphological LR asymmetry in the chick embryo.
Collapse
Affiliation(s)
- M Levin
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | | | | | | | | |
Collapse
|
426
|
Winnier G, Blessing M, Labosky PA, Hogan BL. Bone morphogenetic protein-4 is required for mesoderm formation and patterning in the mouse. Genes Dev 1995; 9:2105-16. [PMID: 7657163 DOI: 10.1101/gad.9.17.2105] [Citation(s) in RCA: 1323] [Impact Index Per Article: 45.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Bone morphogenetic protein-4 (BMP-4) is a member of the TGF-beta superfamily of polypeptide signaling molecules, closely related to BMP-2 and to Drosophila decapentaplegic (DPP). To elucidate the role of BMP-4 in mouse development the gene has been inactivated by homologous recombination in ES cells. Homozygous mutant Bmp-4tm1blh embryos die between 6.5 and 9.5 days p.c., with a variable phenotype. Most Bmp-4tm1blh embryos do not proceed beyond the egg cylinder stage, do not express the mesodermal marker T(Brachyury), and show little or no mesodermal differentiation. Some homozygous mutants develop to the head fold or beating heart/early somite stage or beyond. However, they are developmentally retarded and have truncated or disorganized posterior structures and a reduction in extraembryonic mesoderm, including blood islands. These results provide direct genetic evidence that BMP-4 is essential for several different processes in early mouse development, beginning with gastrulation and mesoderm formation. Moreover, in the presumed absence of zygotic ligand, it appears that homozygous mutants can be rescued partially by related proteins or by maternal BMP-4.
Collapse
Affiliation(s)
- G Winnier
- Howard Hughes Medical Institute, Vanderbilt University Medical School, Nashville, Tennessee 37232-2175, USA
| | | | | | | |
Collapse
|
427
|
|
428
|
|
429
|
Smith WC, McKendry R, Ribisi S, Harland RM. A nodal-related gene defines a physical and functional domain within the Spemann organizer. Cell 1995; 82:37-46. [PMID: 7606783 DOI: 10.1016/0092-8674(95)90050-0] [Citation(s) in RCA: 269] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A functional screen for gene products that rescue dorsal development in ventralized Xenopus embryos has yielded Xenopus nodal-related 3 (Xnr3), a diverged member of the TGF beta superfamily. Xnr3 is specifically expressed in the Spemann organizer and is only expressed in the epithelial layer of the organizer immediately preceding and extending through gastrulation. Like noggin, Xnr3 can induce muscle in ventral mesoderm explants, consistent with a role in patterning the gastrula. In other ways, the activity of Xnr3 is different from noggin. Embryos receiving injections of Xnr3, particularly in the animal pole, send out tube-like extensions of tissue from the site of injection. These protrusions usually contain no axial mesoderm and only occasionally are positive for neural markers. It has previously been proposed that the epithelial layer of the organizer initiates and coordinates the morphogenetic movements at gastrulation. The protrusions observed may reflect an activity of Xnr3 in promoting morphogenesis.
Collapse
Affiliation(s)
- W C Smith
- Department of Molecular and Cell Biology University of California, Berkeley 94720, USA
| | | | | | | |
Collapse
|
430
|
Brändli AW, Kirschner MW. Molecular cloning of tyrosine kinases in the early Xenopus embryo: identification of Eck-related genes expressed in cranial neural crest cells of the second (hyoid) arch. Dev Dyn 1995; 203:119-40. [PMID: 7655077 DOI: 10.1002/aja.1002030202] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Growth factors and their receptors play an important role in controlling cellular proliferation, migration, and differentiation during vertebrate embryogenesis. We have used the reverse transcription-polymerase chain reaction to survey the repertoire of receptor tyrosine kinases (TK) expressed during early embryogenesis of Xenopus laevis. Twelve distinct Xenopus TK cDNA classes were identified among a total of 352 cDNAs screened. A single TK cDNA class has been described previously and encodes the fibroblast growth factor receptor FGFR-A1. The remaining 11 TK cDNA classes appear to encode novel genes of the FGFR, platelet-derived growth factor receptor (PDGFR), Eph, Csk, Tyk2, and Klg subfamilies. By RNase protection assays, Xenopus TK mRNAs are rare transcripts (< 10(7) mRNA molecules/embryo), and are usually found to be expressed also maternally in the embryo. Most Xenopus TK genes examined by whole-mount in situ hybridization were expressed widely in tissues derived from multiple germ layers. Two Eck-related genes, however, were found to be restricted in their expression to neural crest of the second (hyoid) arch. Our findings are consistent with the proposed function of TKs in the regulation of specification and differentiation of embryonic tissues.
Collapse
Affiliation(s)
- A W Brändli
- Department of Biochemistry and Biophysics, School of Medicine, University of California, San Francisco 94143-0448, USA
| | | |
Collapse
|
431
|
Matzuk MM. Functional analysis of mammalian members of the transforming growth factor-beta superfamily. Trends Endocrinol Metab 1995; 6:120-7. [PMID: 18406693 DOI: 10.1016/1043-2760(95)00032-d] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Analysis of growth factor function has come from studies both in vitro and in vivo. However, the generation of mice deficient in a specific growth factor via gene targeting (for example, "knockout") strategies in embryonic stem (ES) cells will often evaluate the essential roles of the protein in vivo and, in many cases, discover new functions. In this review, studies to date are discussed on the generation and analysis of mice deficient in members of the transforming growth factor (TGF-beta) superfamily. Among the genes targeted via ES cell strategies are the TGF-beta1, Müllerian-inhibiting substance (MIS), inhibin alpha, activin betaA, and activin betaB genes. In addition, the mouse short ear and brachypodism mutants and insertional mutant 413-d have been identified as mutations in the BMP-5, GDF-5, and nodal loci, respectively. These studies have led to critical insights into the functions of these gene products and have further emphasized the importance of members of the TGF-beta superfamily in mammalian development, reproduction, and oncogenesis.
Collapse
Affiliation(s)
- M M Matzuk
- The Departments of Pathology, Cell Biology, and Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| |
Collapse
|
432
|
Erickson RP. Recent advances in developmental genetics: growth factors and morphogens. Mol Reprod Dev 1995; 41:109-25. [PMID: 7619500 DOI: 10.1002/mrd.1080410116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- R P Erickson
- Department of Pediatrics, Steele Memorial Children's Research Center, University of Arizona College of Medicine, Tucson 85724, USA
| |
Collapse
|
433
|
Abstract
Lim1 is a homeobox gene expressed in the organizer region of mouse embryos. To investigate the role of Lim1 during embryogenesis, a targeted deletion of the Lim1 gene was generated in embryonic stem cells. Embryos homozygous for the null allele lacked anterior head structures but the remaining body axis developed normally. A partial secondary axis developed anteriorly in some mutant embryos. Lim1 is thus an essential regulator of the vertebrate head organizer.
Collapse
Affiliation(s)
- W Shawlot
- Department of Molecular Genetics, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA
| | | |
Collapse
|
434
|
|
435
|
Matzuk MM, Kumar TR, Vassalli A, Bickenbach JR, Roop DR, Jaenisch R, Bradley A. Functional analysis of activins during mammalian development. Nature 1995; 374:354-6. [PMID: 7885473 DOI: 10.1038/374354a0] [Citation(s) in RCA: 452] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Activins are dimeric (beta A beta A; beta B beta B; beta A beta B) members of the transforming growth factor-beta superfamily. They are widely expressed during murine development, are highly conserved during vertebrate evolution, and may be involved in mesoderm induction and neurulation in Xenopus laevis and Oryzias latipes. To investigate the function of mammalian activins in vivo, we generated mice with mutations either in activin-beta A or in both activin-beta A and activin-beta B. Activin-beta A-deficient mice develop to term but die within 24 h of birth. They lack whiskers and lower incisors and have defects in their secondary palates, including cleft palate, demonstrating that activin-beta A must have a role during craniofacial development. Mice lacking both activin subunits show the defects of both individual mutants but no additional defects, indicating that there is no functional redundancy between these proteins during embryogenesis. In contrast to observations in lower vertebrates, zygotic expression of activins is not essential for mesoderm formation in mice.
Collapse
Affiliation(s)
- M M Matzuk
- Department of Molecular and Human Genetics, Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas 77030
| | | | | | | | | | | | | |
Collapse
|
436
|
Abstract
A survey of mouse gene knockouts, transgene insertions and spontaneous mutations that are lethal prenatally reveals that surprisingly few developmental disturbances lead to death of the embryo and early foetus. These disturbances include failure to establish and maintain a vascular circulation, and failure to make the transition from yolk-sac-based to liver-based haematopoiesis. The embryo must also establish gestation-dependent routes of nutritional interaction with the mother, including implantation, formation of a yolk-sac vascular circulation, and formation of a chorioallantoic placenta. A number of embryonic organ and body systems, including the central nervous system, gut, lungs, urogenital system and musculoskeletal system, appear to have little or no survival value in utero.
Collapse
Affiliation(s)
- A J Copp
- Developmental Biology Unit, University of London, UK
| |
Collapse
|
437
|
Streit A, Stern CD, Théry C, Ireland GW, Aparicio S, Sharpe MJ, Gherardi E. A role for HGF/SF in neural induction and its expression in Hensen's node during gastrulation. Development 1995; 121:813-24. [PMID: 7720585 DOI: 10.1242/dev.121.3.813] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
It was previously shown (Roberts, C., Platt, N., Streit, A., Schachner, M. and Stern, C. D. (1991) Development 112, 959–970) that grafts of Hensen's node into chick embryos enhanced and maintain expression of the L5 carbohydrate in neighbouring epiblast cells, and that antibodies against L5 inhibit neural induction by such a graft. We now show that L5 is initially widely expressed in the epiblast, but as neural induction proceeds it gradually becomes confined to and up-regulated in the early neural plate. L5 can therefore be considered as a marker for cells that are competent to respond to neural induction. We also show that Hepatocyte Growth Factor/Scatter Factor (HGF/SF) promotes the expression of L5 by extraembryonic epiblast in collagen gels after overnight culture. Explants cultured for several days in the presence of HGF/SF, as well as explants of prospective neural plate, can differentiate into cells with neuronal morphology expressing neuronal markers. To investigate whether HGF/SF is expressed in the chick embryo at appropriate stages of development, we produced specific cDNA probes and used them for in situ hybridization. We find that at the primitive streak stage, HGF/SF is expressed specifically in Hensen's node. We therefore propose that HGF/SF plays a role during the early steps of neural induction, perhaps by inducing or maintaining the competence of the epiblast to respond to neural inducing signals.
Collapse
|
438
|
Robinson ML, Overbeek PA, Verran DJ, Grizzle WE, Stockard CR, Friesel R, Maciag T, Thompson JA. Extracellular FGF-1 acts as a lens differentiation factor in transgenic mice. Development 1995; 121:505-14. [PMID: 7539358 DOI: 10.1242/dev.121.2.505] [Citation(s) in RCA: 149] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The vertebrate ocular lens undergoes a spatially defined pattern of differentiation which may be regulated by the ocular distribution of proteins from the fibroblast growth factor (FGF) family. The ability of altered FGF-1 (acidic FGF) distribution to disrupt the normal pattern of lens differentiation was evaluated by the production of transgenic mice which express FGF-1 under the control of the lens-specific alpha A-crystallin promoter. Since FGF-1 lacks a classical signal peptide consensus sequence, transgenic mice were also produced with a chimeric construct containing the signal peptide sequence of the FGF-4 gene fused in frame to the coding sequences of the FGF-1 cDNA in order to obtain extracellular expression of the transgene. The presence of transgenic mRNA and protein was confirmed by in situ hybridization, Western analysis and immunohistochemistry. The ocular histology of newborn and young adult transgenic mice expressing FGF-1 without a signal peptide appeared normal. In contrast, mice expressing secreted FGF-1 exhibited lens abnormalities including the elongation of anterior epithelial cells. Epithelial cell elongation was accompanied by expression of the fiber cell differentiation marker, beta-crystallin. These observations provide an in vivo demonstration that FGF-1 can induce anterior lens epithelial cells to express characteristics consistent with the onset of fiber cell differentiation. The transgenic induction of differentiation confirms that normal lens morphology reflects an asymmetric distribution of inductive factors within the eye.
Collapse
Affiliation(s)
- M L Robinson
- Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | | | | | | | | | | | | | | |
Collapse
|
439
|
Faust C, Schumacher A, Holdener B, Magnuson T. The eed mutation disrupts anterior mesoderm production in mice. Development 1995; 121:273-85. [PMID: 7768172 DOI: 10.1242/dev.121.2.273] [Citation(s) in RCA: 216] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mouse embryos homozygous for the mutation embryonic ectoderm development (eed) exhibit a growth defect and fail to gastrulate normally. While extraembryonic mesoderm is produced extensively, very little embryonic mesoderm is detected in eed mutant embryos, and there is no subsequent organization of mesoderm into node, notochord, or somites. The phenotype is consistent with a defect in the distal primitive streak. Here we report additional phenotypic analyses that include mRNA in situ hybridization of genes whose expression reflects the function of different regions of the primitive streak and their derivatives. These studies have confirmed that mesoderm derived from the proximal primitive streak is specified appropriately. Despite the absence of a morphologically distinct node, sparse axial mesoderm cells in eed mutant embryos are specified, as reflected by expression of Brachyury (T), Sonic hedgehog, and Tcf3b/HNF-3 beta, and definitive endoderm is produced. Specification of these cell types is also independent of correct expression of nodal, Fgf4, and gsc. Finally, T and Evx1 display ectopic expression in cells not normally fated to ingress through the primitive streak. The data presented are discussed in terms of mechanisms for establishment of the eed phenotype, and are consistent with the eed gene product playing an early role in primitive streak formation and/or organization.
Collapse
Affiliation(s)
- C Faust
- Department of Genetics, Case Western Reserve University, Cleveland, Ohio 44106-4955, USA
| | | | | | | |
Collapse
|
440
|
Toyama R, O'Connell ML, Wright CV, Kuehn MR, Dawid IB. Nodal induces ectopic goosecoid and lim1 expression and axis duplication in zebrafish. Development 1995; 121:383-91. [PMID: 7768180 DOI: 10.1242/dev.121.2.383] [Citation(s) in RCA: 127] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
One of the first intercellular signalling events in the vertebrate embryo leads to mesoderm formation and axis determination. In the mouse, a gene encoding a new member of the TGF-beta superfamily, nodal, is disrupted in a mutant deficient in mesoderm formation (Zhou et al., 1993, Nature 361, 543). nodal mRNA is found in prestreak mouse embryos, consistent with a role in the development of the dorsal axis. To examine the biological activities of nodal, we have studied the action of this factor in eliciting axis determination in the zebrafish, Danio rerio. Injection of nodal mRNA into zebrafish embryos caused the formation of ectopic axes that included notochord and somites. Axis duplication was preceded by the generation of an apparent ectopic shield (organizer equivalent) in nodal-injected embryos, as indicated by the appearance of a region over-expressing gsc and lim1; isolation and expression in the shield of the lim1 gene is reported here. These results suggest a role for a nodal-like factor in pattern formation in zebrafish.
Collapse
Affiliation(s)
- R Toyama
- Laboratory of Molecular Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | | | | | |
Collapse
|
441
|
Rissi M, Wittbrodt J, Délot E, Naegeli M, Rosa FM. Zebrafish Radar: a new member of the TGF-beta superfamily defines dorsal regions of the neural plate and the embryonic retina. Mech Dev 1995; 49:223-34. [PMID: 7734395 DOI: 10.1016/0925-4773(94)00320-m] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Proper development of metazoan embryos requires cell to cell communications. In many instances, these communications involve diffusible molecules, particularly members of the Transforming Growth Factor beta superfamily. In an effort to identify new members of this superfamily involved in the control of early zebrafish embryogenesis, we have isolated a gene, Radar, which appears to be conserved throughout vertebrate evolution and defines a new subfamily within the superfamily. Its pattern of expression suggests that Radar plays a role in the dorso-ventral polarity of the neural plate, blood islands formation, blood cells differentiation, the establishment of retinal dorso-ventral polarity and/or proper axonal retinotectal projections. Radar expression in ntl homozygous mutants indicates that notochord and hypochord development are intimately linked.
Collapse
Affiliation(s)
- M Rissi
- Department of Cell Biology, Biozentrum der Universität, Basel, Switzerland
| | | | | | | | | |
Collapse
|
442
|
Cunningham NS, Jenkins NA, Gilbert DJ, Copeland NG, Reddi AH, Lee SJ. Growth/differentiation factor-10: a new member of the transforming growth factor-beta superfamily related to bone morphogenetic protein-3. Growth Factors 1995; 12:99-109. [PMID: 8679252 DOI: 10.3109/08977199509028956] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We have identified a new member of the transforming growth factor-beta (TGF-beta) superfamily, growth/differentiation factor-10 (GDF-10), which is highly related to bone morphogenetic protein-3 (BMP-3). The nucleotide sequence of GDF-10 encodes a predicted protein of 476 amino acids with a molecular weight of approximately 52,000. The GDF-10 polypeptide contains a potential signal sequence for secretion, a putative RXXR proteolytic processing site, and a carboxy-terminal domain with considerable homology to other known members of the TGF-beta superfamily. In the mature carboxy-terminal domain GDF-10 is more homologous to BMP-3 (83% amino acid sequence identity) than to any other previously identified TGF-beta family member. GDF-10 also shows significant homology to BMP-3 (approximately 30% amino acid sequence identity) in the pro- region of the molecule. Based on these sequence comparisons, GDF-10 and BMP-3 define a new subgroup within the larger TGF-beta superfamily. By Northern analysis, GDF-10 mRNA was detected primarily in murine uterus, adipose tissue, and brain and to a lesser extent in liver and spleen. In addition, GDF-10 mRNA was present in both neonatal and adult bone samples, with higher levels being detected in calvaria than in long bone. These results suggest that GDF10 may play multiple roles in regulating cell differentiation events, including those involved in skeletal morphogenesis. Gdf10 was mapped to the proximal region of mouse chromosome 14 close to a region known to contain a spontaneous recessive mutation that is associated with a craniofacial defect.
Collapse
Affiliation(s)
- N S Cunningham
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | | | | | | | | | | |
Collapse
|
443
|
Johansson BM, Wiles MV. Evidence for involvement of activin A and bone morphogenetic protein 4 in mammalian mesoderm and hematopoietic development. Mol Cell Biol 1995; 15:141-51. [PMID: 7799920 PMCID: PMC231923 DOI: 10.1128/mcb.15.1.141] [Citation(s) in RCA: 363] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Xenopus in vitro studies have implicated both transforming growth factor beta (TGF-beta) and fibroblast growth factor (FGF) families in mesoderm induction. Although members of both families are present during mouse mesoderm formation, there is little evidence for their functional role in mesoderm induction. We show that mouse embryonic stem cells, which resemble primitive ectoderm, can differentiate to mesoderm in vitro in a chemically defined medium (CDM) in the absence of fetal bovine serum. In CDM, this differentiation is responsive to TGF-beta family members in a concentration-dependent manner, with activin A mediating the formation of dorsoanterior-like mesoderm and bone morphogenetic protein 4 mediating the formation of ventral mesoderm, including hematopoietic precursors. These effects are not observed in CDM alone or when TGF-beta 1, -beta 2, or -beta 3, acid FGF, or basic FGF is added individually to CDM. In vivo, at day 6.5 of mouse development, activin beta A RNA is detectable in the decidua and bone morphogenetic protein 4 RNA is detectable in the egg cylinder. Together, our data strongly implicate the TGF-beta family in mammalian mesoderm development and hematopoietic cell formation.
Collapse
|
444
|
Gasca S, Hill DP, Klingensmith J, Rossant J. Characterization of a gene trap insertion into a novel gene, cordon-bleu, expressed in axial structures of the gastrulating mouse embryo. DEVELOPMENTAL GENETICS 1995; 17:141-54. [PMID: 7586755 DOI: 10.1002/dvg.1020170206] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have used a gene trap (GT) vector and embryonic stem (ES) cell chimeras to screen for insertions of the lacZ reporter gene into transcription units that are spatially and temporally regulated during early mouse embryogenesis. GT vectors which can act as both a reporter and a mutagen have been previously used to isolate new genes that are essential for mouse development. In this paper we describe a GT insertion which displays a very restricted pattern of expression in the gastrulating embryo. beta-Galactosidase activity was first detected at 7.5 days post-coitum (E7.5) in the node region of the embryo and extended to the midline structures at E8.0. At E9.5 expression was restricted to the floor plate, the notochord, the roof of the gut, and the liver anlage. Expression appeared in the somites at E10.0 and later became more widespread. We used rapid amplification of cDNA ends-polymerase chain reaction (RACE-PCR) to clone a partial 360 base pair (bp) cDNA representing an endogenous sequence and containing an open reading frame (ORF) fused in frame to the lacZ reporter gene. The sequence showed no homology to any known protein or protein domain. An overlapping 1,200 bp fragment from a wild-type cDNA library was cloned and it detected the same pattern of expression as the reporter gene in E7.5, E8.5, and E9.5 wild-type embryos. It hybridized to a 5.4 kb lacZ fusion transcript and to an endogenous transcript of 6.5 kb. The gene was mapped to chromosome 11 and was named cordon-bleu (cobl). No phenotype was detected in mice homozygous for the insertion. However, the insertion may not cause a complete disruption of the gene function. The pattern of expression of cobl is very similar to that of hepatic nuclear factor 3 beta (HNF3 beta) and sonic hedgehog (Shh), both of which are involved in axial patterning. Therefore, the product of the cobl gene may also prove to be an important component of the genetic pathway regulating vertebrate axis formation.
Collapse
Affiliation(s)
- S Gasca
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | | | | | | |
Collapse
|
445
|
Gaddy-Kurten D, Tsuchida K, Vale W. Activins and the receptor serine kinase superfamily. RECENT PROGRESS IN HORMONE RESEARCH 1995; 50:109-29. [PMID: 7740154 DOI: 10.1016/b978-0-12-571150-0.50010-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- D Gaddy-Kurten
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute, La Jolla, California 92037, USA
| | | | | |
Collapse
|
446
|
Yamaguchi TP, Harpal K, Henkemeyer M, Rossant J. fgfr-1 is required for embryonic growth and mesodermal patterning during mouse gastrulation. Genes Dev 1994; 8:3032-44. [PMID: 8001822 DOI: 10.1101/gad.8.24.3032] [Citation(s) in RCA: 560] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Experiments in amphibians have implicated fibroblast growth factors (FGFs) in the generation and patterning of mesoderm during embryogenesis. We have mutated the gene for fibroblast growth factor receptor 1 (fgfr-1) in the mouse to genetically dissect the role of FGF signaling during development. In the absence of fgfr-1 signaling, embryos displayed early growth defects; however, they remained capable of gastrulating and generating mesoderm. The nascent mesoderm of fgfr-1 homozygous mutant embryos differentiated into diverse mesodermal subtypes, but mesodermal patterning was aberrant. Somites were never generated and axial mesoderm was greatly expanded at the expense of paraxial mesoderm. These results suggest that FGFR-1 transduces signals that specify mesodermal cell fates and regional patterning of the mesoderm during gastrulation.
Collapse
MESH Headings
- Animals
- Base Sequence
- Cloning, Molecular
- Crosses, Genetic
- DNA Primers
- Embryonic and Fetal Development
- Exons
- Female
- Fetal Death
- Fibroblast Growth Factors/physiology
- Gastrula/physiology
- Genes, Lethal
- Genetic Markers
- Genotype
- Heterozygote
- Kanamycin Kinase
- Male
- Mesoderm/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Inbred Strains
- Mice, Transgenic
- Molecular Sequence Data
- Phosphotransferases (Alcohol Group Acceptor)/analysis
- Phosphotransferases (Alcohol Group Acceptor)/biosynthesis
- Polymerase Chain Reaction
- Pregnancy
- Receptor Protein-Tyrosine Kinases
- Receptor, Fibroblast Growth Factor, Type 1
- Receptors, Fibroblast Growth Factor/biosynthesis
- Receptors, Fibroblast Growth Factor/genetics
- Receptors, Fibroblast Growth Factor/physiology
- Restriction Mapping
- Signal Transduction
Collapse
Affiliation(s)
- T P Yamaguchi
- Samuel Lunenfeld Research Institute (SLRI), Mount Sinai Hospital, Toronto, Ontario, Canada
| | | | | | | |
Collapse
|
447
|
Mardon G, Solomon NM, Rubin GM. dachshund encodes a nuclear protein required for normal eye and leg development in Drosophila. Development 1994; 120:3473-86. [PMID: 7821215 DOI: 10.1242/dev.120.12.3473] [Citation(s) in RCA: 374] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Neural specification and differentiation in the Drosophila eye sweep across the unpatterned epithelial monolayer of the eye imaginal disc following a developmental wave termed the morphogenetic furrow. The furrow begins at the posterior margin of the eye imaginal disc and moves anteriorly as a linear front. Progression of the furrow requires the function of hedgehog, which encodes a secreted signaling protein. We characterize mutations in dachshund, a gene that encodes a novel nuclear protein required for normal cell-fate determination of imaginal disc cells. In the absence of dachshund function, cells at the posterior margin of the eye disc fail to follow a retinal differentiation pathway and appear to adopt a cuticle fate instead. These cells are therefore unable to respond to pattern propagation signals such as hedgehog and furrow initiation does not occur. In contrast, cells in more anterior portions of the eye disc are able to differentiate as retinal cells in the absence of dachshund activity and respond normally to patterning signals. These results suggest that posterior margin cells are distinct from other cells of the eye imaginal disc by early stages of development. dachshund is also necessary for proper differentiation of a subset of segments in the developing leg. Null mutations in dachshund result in flies with no eyes and shortened legs.
Collapse
Affiliation(s)
- G Mardon
- Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley 94720-3200
| | | | | |
Collapse
|
448
|
Abstract
Within the fertilized egg lies the information necessary to generate a diversity of cell types in the precise pattern of tissues and organs that comprises the vertebrate body. Seminal embryological experiments established the importance of induction, or cell interactions, in the formation of embryonic tissues and provided a foundation for molecular studies. In recent years, secreted gene products capable of inducing or patterning embryonic tissues have been identified. Despite these advances, embryologists remain challenged by fundamental questions: What are the endogenous inducing molecules? How is the action of an inducer spatially and temporally restricted? How does a limited group of inducers give rise to diversity of tissues? In this review, the focus is on the induction and patterning of mesodermal and neural tissues in the frog Xenopus laevis, with an emphasis on families of secreted molecules that appear to underlie inductive events throughout vertebrate embryogenesis.
Collapse
Affiliation(s)
- D S Kessler
- Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138
| | | |
Collapse
|
449
|
Chen WS, Manova K, Weinstein DC, Duncan SA, Plump AS, Prezioso VR, Bachvarova RF, Darnell JE. Disruption of the HNF-4 gene, expressed in visceral endoderm, leads to cell death in embryonic ectoderm and impaired gastrulation of mouse embryos. Genes Dev 1994; 8:2466-77. [PMID: 7958910 DOI: 10.1101/gad.8.20.2466] [Citation(s) in RCA: 420] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Expression of HNF-4, a transcription factor in the steroid hormone receptor superfamily, is detected only in the visceral endoderm of mouse embryos during gastrulation and is expressed in certain embryonic tissues from 8.5 days of gestation. To examine the role of HNF-4 during embryonic development, we disrupted the gene in embryonic stem cells and found that the homozygous loss of functional HNF-4 protein was an embryonic lethal. Cell death was evident in the embryonic ectoderm at 6.5 days when these cells normally initiate gastrulation. As assessed by expression of Brachyury and HNF-3 beta, primitive streak formation and initial differentiation of mesoderm do occur, but with a delay of approximately 24 h. Development of embryonic structures is severely impaired. These results demonstrate that the expression of HNF-4 in the visceral endoderm is essential for embryonic ectoderm survival and normal gastrulation.
Collapse
Affiliation(s)
- W S Chen
- Laboratory of Molecular Cell Biology, Rockefeller University, New York, New York 10021
| | | | | | | | | | | | | | | |
Collapse
|
450
|
Abstract
Analysis of HNF-3beta mutant mice demonstrates that the HNF-3beta transcription factor is an important regulator of the gastrulating mouse embryo.
Collapse
Affiliation(s)
- A P McMahon
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138
| |
Collapse
|