1982 — 1984 |
Papaioannou, Virginia |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Mutant and Neoplastic Cells in Mammalian Embryogenesis |
0.966 |
1986 — 1988 |
Papaioannou, Virginia E. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Embryo Viability as Assessed by Icm/Trophectoderm Ratio @ Tufts University Boston
This study is designed to explore the relationship between the ratio of differentiated cell types, inner cell mass (ICM) and trophectoderm, at the time of blastulation and the developmental potential of the embryo. Since cell position in the morula determines the direction of differentiation, a predictable relationship should exist between total cell number in the morula and ratio of ICM to trophectoderm in the blastocyst. A recently devised, vital method of cell counting, using the DNA dye bisbenzimide, which does not affect developmental potential of embryos should provide a simple, noninvasive means of determining embryonic potential once this relationship is established. Assessment of viability by embryo transfer and development to midgestation provides the most stringent test of normality which distinguishes between simple metabolic functioning and true developmental potential of the embryo as a whole. The relationship between cell number and ratio in the blastocyst and its relevance to developmental potential will first be examined in the mouse. Differential cell counts of ICM and trophectoderm will be made in embryos doubly dyed with bisbenzimide and propidium iodide (PI) following specific lysis of trophectoderm by immunosurgery. All cells are permeable to bisbenzimide whereas only nuclei of lysed cells will stain with PI. Microsurgery will be used to reduce cell number and effects of culture or development in vivo in an immature mouse oviduct as a surrogate environment will be examined to test cell ratio and viability relationships over a wide range of conditions. Ascertainment of the nature of developmental abnormalities encountered will contribute to the long term goal of relating specific fetal abnormalities to specific developmental parameters of the preimplantation embryo. The normal range of these parameters will then be examined in the pig to explore the possibility that inherent differences among early embryos could account for the high embryonic wastage characteristic of the pig and humans. Since ethical considerations limit experimental techniques applied to human embryos, it is important to test the general applicability of mechanisms in a range of species before making assumptions of similarity. A long term goal is that a greater understanding of factors that affect develpmental potential will aid in the interpretation of human embryonic development.
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0.911 |
1989 — 1991 |
Papaioannou, Virginia E. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Role of Trophectoderm Subpopulations in Implantation @ Tufts University Boston
trophoblast; embryo implantation; cell cell interaction; mammalian embryology; endometrium; embryo /fetus transplantation; early embryonic stage; cytoskeleton; stromal cells; cell type; embryo /fetus cell /tissue; uterus; proteolysis; fluorescence microscopy; swine; laboratory mouse;
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0.911 |
1990 — 1994 |
Papaioannou, Virginia E. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Expression/Function of C Fos and C Jun in Development @ Tufts University Boston
The goals of this proposal are to investigate the role of proto-oncogenes in normal mammalian development and to understand how aberrations in the expression of these genes could result in pregnancy wastage or congenital malformations. C-fos and c-jun proto-oncogenes function together to regulate gene expression at the molecular level and have been chosen for this study as proto-oncogenes implicated in development. C-fos is expressed in a tissue-specific manner during embryogenesis and shows high levels of expression in extraembryonic tissues. These tissues play an essential role in implantation and in the survival of the embryo during the postimplantation period. It is our hypothesis that tissue-specific expression reflects a functional requirement for the c-fos gene product. We further postulate that c-jun will be expressed in a similar manner and will also be required during development. The specific aims of this proposal are to clarify the extent of c-fos and c-jun expression throughout the pre- and early postimplantation period in the mouse and examine the functional role of these genes in development. This will be accomplished by the following specific aims: Specific Aim I. We will detail the expression of c-fos and c-jun during pre- and postimplantation mouse development using in situ hybridization for RNA localization and immunohistochemistry for localization of the proteins. Specific Aim 2. We will produce embryonic stem (ES) cell lines heterozygous for mutated c-fos and c-jun by gene targeting via homologous recombination. Preliminary results have been successful in targeting c-fos and one mutated clone is now available. Specific Aim 3. We will then produce transgenic animals heterozygous and homozygous for mutated C-fos or c-jun by way of ES cell chimeras, in order to determine the effect of a lower dose or absence of c-fos or c-jun gene product on development. One series of chimeras is already being test-bred to produce heterozygous mice. If we determine that heterozygous cells are not capable of completing gametogenesis in a chimera, an alternative, rescue protocol will be used that will allow the study of gametogenesis in heterozygous males.
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0.911 |
1996 — 2000 |
Papaioannou, Virginia E. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Expression and Role of T-Box Genes in Mouse Development @ Columbia University Health Sciences
The long-term objectives of the proposed research are to characterize the members of a newly discovered, ancient family of embryonically-expressed mouse genes, the T-box genes, and to determine the functional roles they play in embryonic development. These genes share a conserved proton motif, the T-box, which co-localizes with the DNA binding activity of the prototypical T locus of the mouse, a locus which regulates mesoderm formation. Because of the evolutionary conservation between widely divergent species from nematode to mouse, these genes are likely to play a role in the development of all vertebrates. Our preliminary results with 6 newly discovered T-box genes reveal temporal and spatial expression patterns during embryogenesis, some unique and some overlapping that suggest interactive roles for these genes in different aspects of development. We will detail the expression of these genes and critically test their functional roles using mutational analysis. Although the research has specific goals that will be accomplished for the individual genes already identified, the overall objective is much broader in scope, and encompasses an attempt to understand the relationship between the various members of the gene families, and the basis of the evolutionary conservation of the shared motif. It is our belief, based our expression data and by analogy with other gene families with conserved, shared motifs such as Hox and Pax, that the T-box family of genes encodes a set of DNA binding proteins that each play a distinctive role in developmental signaling. our intention is to add new T-box genes to our investigation as they are identified and to concentrate efforts on individual genes or groups of related genes that appear most informative in elucidating developmental mechanisms. In order to accomplish this larger aim, this proposal is one component of a two-part Investigator-Initiated Interactive Research Project Grant (IRPG). Our collaborator, Dr. Lee Silver of Princeton University has been funded to pursue complementary work in his laboratory. The submission of this proposal as an IRPG reflects our shared objectives, complementary expertise and intention of continuing our existing collaborative arrangement to investigate this ancient family of mouse genes. Specific Aim 1. Determine the expression pattern of mouse T-box genes, 1- 6, during embryogenesis, organogenesis and in the adult. We will use Northern blot analysis, in situ hybridization of tissue sections and whole mounts, and gene targeting constructs that include a marker gene driven by the endogenous promoter. Specific Aim 2. To determine the function of T-box genes by creating null mutations using homologous recombination in embryonic stem cells. The phenotype of resulting mutant animals will be analyzed and the mutants will be mated together to study possible interactions between different genes.
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0.958 |
1996 — 2015 |
Papaioannou, Virginia E. |
T32Activity Code Description: To enable institutions to make National Research Service Awards to individuals selected by them for predoctoral and postdoctoral research training in specified shortage areas. |
Predoctoral Training Grant in Genetics and Development @ Columbia University Health Sciences |
0.958 |
2000 |
Papaioannou, Virginia E. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Determination of Embryonic Polarity @ Columbia University Health Sciences
During the early stages on embryonic development, the formation of the embryonic axis is initiated at one pole of the embryo. Most of what is known about the molecular mechanisms underlying this process is based on amphibian embryos, where maternally-derived determinants control this polarity. In amniotes (birds and mammals) this is unlikely because embryos at much later stages can initiate axis formation at any position. Here, the mechanisms that determine embryonic polarity in the early stages of development will be studied using the chick embryo as a model, because of their ease of manipulation and culture. First, the role of the hypoblast (which had been suggested to be responsible for polarity determination) will be tested directly. Then, the region homologous to the amphibian "Nieuwkoop center" (which has been shown in frogs to determine the position of future "organizer" and axial cells) will be located. Finally, a number of genes already found to be expressed in a way that predicts the future polarity of the embryo will be placed in hierarchial order, taking advantage of the fact that portions of the embryo will initiate axis formation when isolated from the rest of the embryo. The results of this project will be of value in suggesting how the molecular cascades that have been implicated in the early development of lower vertebrates (fish, amphibians) can be applied to higher vertebrates (birds and mammals). Potentially, knowledge of these cascades could lead to the development of new molecular diagnostic tools for some of the many serious congenital disorders that affect the early development of the embryonic axis, and may help determine whether monozygotic and conjoined twinning are likely to have a molecular basis.
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0.958 |
2000 — 2003 |
Papaioannou, Virginia |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Role of Fibroblast Growth Factor - 4 in the Early Mouse Embryo
Papaioannou 9985953
Stem cells are self renewing. That is, they divide and give rise to a cell that differentiates as well as a cell that maintains its identity as a stem cell. Understanding how stem cells are regulated is fundamental to understanding how mutlicellular organisms form. Dr. Papioannou is investigating the potential role of growth factors in regulating stem cell populations. Given the critical role of stem cells in development, this work will lead to a deeper understanding of the regulation of embryo development.
Fibroblast growth factors (FGFs) comprise a family of related signaling molecules that bind and activate fibroblast growth factor receptors (FGFRs). FGF-4, which is expressed in the inner cell mass (ICM) of the blastocyst and in the later epiblast, is essential for peri-implantation development. Mouse embryos lacking this factor through gene targeting of Fgf4 implant in the uterus but fail to undergo further development. The experiments proposed will investigate the potential role of FGF-4 as a stem cell factor in early embryos by examining three hypotheses: (1) FGF-4 is an autocrine proliferation or survival factor for the ICM. (2) FGF-4 promotes the differentiation of primitive endoderm. (3) FGF-4 is a paracrine stem cell factor for the diploid trophoblast.
Dr. Papaioannou's first approach will be a detailed examination of cell number and differentiated cell distribution in mutant Fgf4 embryos throughout peri-implantation development. The second will be to attempt rescue of mutant effects by supplying exogenous recombinant FGF-4 to intact embryos. The third approach makes use of chimera analysis using both mutant embryonic stem (ES) cells combined with normal embryos and vice versa. Each of the hypotheses has specific predictions with respect to the cell composition of chimeras and the potential rescue of the mutant phenotype. Taken together, these studies will provide specific information about the in vivo effect of FGF-4 on stem cell populations of the early embryo and have general implications for the role of FGFs on the control of other embryonic or adult stem cell populations.
|
1 |
2000 — 2003 |
Papaioannou, Virginia E. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Role of Tbx6 in Mesoderm Pattering and Somite Formation @ Columbia University Health Sciences
DESCRIPTION (appended verbatim from investigator's abstract): The objectives of this research are to understand the genetic control of mesoderm specification at gastrulation and to determine how decisions are made at critical junctures between alternative developmental pathways. The hypotheses are 1) that members of the Tbox transcription factor gene family in particular Tbx6 are essential for mesoderm specification and differentiation and 2) that there may be additional members of the Tbx6 subfamily also involved. These hypotheses are based in large part on the null mutation we have produced in Tbx6 and on phylogenetic and mutational studies in other species. The Tbx6 mutation affects the differentiation of mesoderm destined to form the somites and eventually the bulk of the musculoskeletal system. In mutants there is a dramatic switch in the differentiation pathway of posterior mesoderrn to a neural pathway resulting in embryos with three parallel neural tubes and no posterior somites. For all of these studies the mouse will be used as a model system because of its similarity to the human and because of the availability of genetic resources. Understanding the factors that control the development of the musculoskeletal system has important health relatedness for understanding congenital anomalies and chronic diseases of muscles and bone. Specific Aim 1. To determine the lineage of all Tbx6expressing cells in order to characterize fully the phenotypic results of a null mutation in Tbx6 and to examine the developmental potential of Tbx6 null cells. Specific Aim 2.To explore the mechanism of action of Tbx6 in the specification of mesoderm during gastrulation using a Cremediated transgenic approach for misexpression of Tbx6. Specific Aim 3. To produce a new Tbx6 mutant allele coding for a truncated protein with only the DNA binding domain and no transcriptional regulatory domain. Specific Aim 4. To isolate and characterize additional members of the Tbx6 subfamily in the mouse with special emphasis on isolating the orthologs of genes known in other species to play a role in mesoderm development.
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0.958 |
2002 — 2016 |
Papaioannou, Virginia E. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. R37Activity Code Description: To provide long-term grant support to investigators whose research competence and productivity are distinctly superior and who are highly likely to continue to perform in an outstanding manner. Investigators may not apply for a MERIT award. Program staff and/or members of the cognizant National Advisory Council/Board will identify candidates for the MERIT award during the course of review of competing research grant applications prepared and submitted in accordance with regular PHS requirements. |
Role of T-Box Genes in Mouse Development @ Columbia University Health Sciences
The long-term objective of this project is to understand the developmental roles of the T-box family of transcription factor genes and how they interact and impinge on signaling pathways during organogenesis. The work started with an exploration of the evolution of the gene family and the discovery of previously unknown genes in the mammalian genome, eventually defining a family of 17 T-box genes common to mouse and human. A number of these, by virtue of their chromosomal locations, were candidates for human developmental syndromes and our work producing mouse models by targeted mutagenesis validated these predictions. Mutations in human T-box genes were subsequently found to underlie anomalies such as DiGeorge, ulnar-mammary, small patella and Holt-Oram syndromes. There are two main themes to this proposal: to explore how T-box genes interact and to understand how they direct organogenesis through different signaling pathways. To accomplish these goals, we will make use of simple and conditional mutations produced or being produced in our laboratory by targeted mutagenesis as well as mutations from other labs. Several organ systems have been chosen for in-depth study due to interesting patterns of expression of T-box genes and the relevance of the organ systems to important human diseases: Congenital heart defects are a leading cause of death in humans during the first year of life. At least 4 T-box genes play critical roles in heart development and we will continue to explore these gene mutations individually and in combination to understand how they contribute to normal and abnormal development. Tbx2 and Tbx3 interact during early mammary gland development and are implicated in breast cancers. We will continue to explore these roles using conditional alleles. Interesting expression patterns of T-box genes have been uncovered in the gonads and external genitalia and also in the pancreas during islet development. These lines of investigation will be followed to discover the functional role of these genes and their possible involvement in congenital birth defects in the reproductive system or pancreas development relevant to diabetes, respectively.
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0.958 |
2004 — 2005 |
Papaioannou, Virginia E. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Islet Growth in Nod Mice Tolerant to Autoimmune Diabetes @ Columbia University Health Sciences
DESCRIPTION (provided by applicant): The goal of this proposal is to reverse Type 1 diabetes by inducing tolerance to the autoimmune process and replenishing lost islet cells from precursors. Previous clinical studies by Dr. Herold have shown that treatment with an anti-CD3 monoclonal antibody can prevent the loss of insulin production for up to 2 years after onset of diabetes, and preclinical studies suggest that anti-CD3 mAb induces tolerance to the autoimmune disease. However, to establish normal metabolic control, this therapy must be combined with a means of replenishing lost islet tissue. We will test whether, after induction of immunologic tolerance, islets will regenerate, can be stimulated to grow, or whether embryonic stem cells from the pancreatic anlagen may be used to replenish the lost beta cell mass. The proposal will develop a partnership between Dr. Kevan Herold, whose work has been in the immunology and immunotherapy of Type 1 diabetes and Dr. Virginia Papaioannou, who is an expert in the field of developmental biology but who has not previously worked in the field of diabetes. We will first determine whether induction of immune tolerance to autoimmune diabetes in the NOD mouse results in islet cell proliferation. Studies in this aim will include immunohistochemical and molecular analyses of developing insulin+ cells. We will test whether islet cell regeneration can be stimulated using exendin-4 and hepatocyte growth factor which can stimulate beta cell development in non-immune mediated animal models of insulin deficiency. We will test whether stem cells can be grown into islets that can correct diabetes by transplanting pancreatic anlagen from normal MHC matched mice into diabetic NOD mice treated with anti-CD3 mAb. Differentiation into mature pancreatic cells will be studied, and a fluorochrome tagged donor will enable us to identify the source of any newly differentiated insulin+ cell. By comparing this process in the presence or absence of anti-CD3 mAb treatment with hyper or euglycemia, we will be able to obtain additional information including expression of disease relevant islet antigens, and the effects of insulin and glucose on differentiation of islet cells. Drs. Herold and Papaioannou will collaborate closely particularly in the molecular and stem cell studies proposed. By combining the expertise of the two Pl's to address the problems of islet autoimmunity and beta cell deficiency our proposal will test a combination strategy that may be useful in patients.
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0.958 |
2009 — 2010 |
Papaioannou, Virginia E. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
T-Box Gene Effects On Left-Right Body Axis Determination @ Columbia University Health Sciences
The long-term goal of the proposed research is to understand the complex genetic control of determination of left/right (L/R) body axis in the mammalian embryo. Specification of the L/R axis sets up a developmental cascade that coordinates development of the viscera and is essential for the correct placement and alignment of organ systems and vasculature. Defective L/R patterning can lead to congenital cardiac malformations, vascular anomalies and other serious health issues. We will investigate the roles of two T-box transcription factor genes, Brachyury (T) and Tbx6. T has previously been shown to affect laterality in mice although the phenotype has not been fully explored. Tbx6 had not previously been implicated in laterality determination, but our preliminary studies and published work reveals heterotaxia in mutants, indicating an important role for this gene, and shows effects on Notch signaling and cilia within the node. We will investigate these genes to determine the nature and mechanism of the defects. Understanding how these genes impinge on this basic developmental process will add to understanding of the genetic and morphological landscape within w hich the L/R body axis is determined. Specific Aim 1. To determine the nature and mechanisms of the laterality defects associated with Brachyury (T) mutation in the mouse and place T and Tbx6 in the genetic hierarchy of genes affecting L/R determination. Specific Aim 2. To examine the structure and function of the node and nodal cilia in Tbx6 and T mutant embryos at the time of L/R axis determination. Specific Aim 3. To determine the lineage of cells of the node with respect to their prior expression of Tbx6.
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0.958 |