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  1. Article ; Online: Knockout of Amyloid β Protein Precursor (APP) Expression Alters Synaptogenesis, Neurite Branching and Axonal Morphology of Hippocampal Neurons.

    Southam, Katherine A / Stennard, Fiona / Pavez, Cassandra / Small, David H

    Neurochemical research

    2018  Volume 44, Issue 6, Page(s) 1346–1355

    Abstract: The function of the β-A4 amyloid protein precursor (APP) of Alzheimer's disease (AD) remains unclear. APP has a number of putative roles in neuronal differentiation, survival, synaptogenesis and cell adhesion. In this study, we examined the development ... ...

    Abstract The function of the β-A4 amyloid protein precursor (APP) of Alzheimer's disease (AD) remains unclear. APP has a number of putative roles in neuronal differentiation, survival, synaptogenesis and cell adhesion. In this study, we examined the development of axons, dendrites and synapses in cultures of hippocampus neutrons derived from APP knockout (KO) mice. We report that loss of APP function reduces the branching of cultured hippocampal neurons, resulting in reduced synapse formation. Using a compartmentalised culture approach, we found reduced axonal outgrowth in cultured hippocampal neurons and we also identified abnormal growth characteristics of isolated hippocampal neuron axons. Although APP has previously been suggested to play an important role in promoting cell adhesion, we surprisingly found that APPKO hippocampal neurons adhered more strongly to a poly-L-lysine substrate and their neurites displayed an increased density of focal adhesion puncta. The findings suggest that the function of APP has an important role in both dendritic and axonal growth and that endogenous APP may regulate substrate adhesion of hippocampal neurons. The results may explain neuronal and synaptic morphological abnormalities in APPKO mice and the presence of abnormal APP expression in dystrophic neurites around amyloid deposits in AD.
    MeSH term(s) Amyloid beta-Protein Precursor/deficiency ; Amyloid beta-Protein Precursor/genetics ; Animals ; Axons/metabolism ; Cell Adhesion/physiology ; Dendrites/metabolism ; Female ; Gene Knockout Techniques ; Hippocampus/metabolism ; Mice, Inbred C57BL ; Mice, Knockout ; Neuronal Outgrowth/physiology ; Pregnancy ; Synapses/metabolism
    Chemical Substances Amyloid beta-Protein Precursor
    Language English
    Publishing date 2018-03-23
    Publishing country United States
    Document type Journal Article
    ZDB-ID 199335-5
    ISSN 1573-6903 ; 0364-3190
    ISSN (online) 1573-6903
    ISSN 0364-3190
    DOI 10.1007/s11064-018-2512-0
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: T-box transcription factors and their roles in regulatory hierarchies in the developing heart.

    Stennard, Fiona A / Harvey, Richard P

    Development (Cambridge, England)

    2005  Volume 132, Issue 22, Page(s) 4897–4910

    Abstract: T-box transcription factors are important players in the molecular circuitry that generates lineage diversity and form in the developing embryo. At least seven family members are expressed in the developing mammalian heart, and the human T-box genes TBX1 ...

    Abstract T-box transcription factors are important players in the molecular circuitry that generates lineage diversity and form in the developing embryo. At least seven family members are expressed in the developing mammalian heart, and the human T-box genes TBX1 and TBX5 are mutated in cardiac congenital anomaly syndromes. Here, we review T-box gene function during mammalian heart development in the light of new insights into heart morphogenesis. We see for the first time how hierarchies of transcriptional activation and repression involving multiple T-box factors play out in three-dimensional space to establish the cardiac progenitors fields, to define their subservient lineages, and to generate heart form and function.
    MeSH term(s) Animals ; Gene Expression Regulation, Developmental/physiology ; Heart/embryology ; Heart/physiology ; Humans ; Myocardium/metabolism ; T-Box Domain Proteins/physiology
    Chemical Substances T-Box Domain Proteins
    Language English
    Publishing date 2005-11
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 90607-4
    ISSN 1477-9129 ; 0950-1991
    ISSN (online) 1477-9129
    ISSN 0950-1991
    DOI 10.1242/dev.02099
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Conformational stability and DNA binding specificity of the cardiac T-box transcription factor Tbx20.

    Macindoe, Ingrid / Glockner, Laura / Vukasin, Paul / Stennard, Fiona A / Costa, Mauro W / Harvey, Richard P / Mackay, Joel P / Sunde, Margaret

    Journal of molecular biology

    2009  Volume 389, Issue 3, Page(s) 606–618

    Abstract: The transcription factor Tbx20 acts within a hierarchy of T-box factors in lineage specification and morphogenesis in the mammalian heart and is mutated in congenital heart disease. T-box family members share a approximately 20-kDa DNA-binding domain ... ...

    Abstract The transcription factor Tbx20 acts within a hierarchy of T-box factors in lineage specification and morphogenesis in the mammalian heart and is mutated in congenital heart disease. T-box family members share a approximately 20-kDa DNA-binding domain termed the T-box. The question of how highly homologous T-box proteins achieve differential transcriptional control in heart development, while apparently binding to the same DNA sequence, remains unresolved. Here we show that the optimal DNA recognition sequence for the T-box of Tbx20 corresponds to a T-half-site. Furthermore, we demonstrate using purified recombinant domains that distinct T-boxes show significant differences in the affinity and kinetics of binding and in conformational stability, with the T-box of Tbx20 displaying molten globule character. Our data highlight unique features of Tbx20 and suggest mechanistic ways in which cardiac T-box factors might interact synergistically and/or competitively within the cardiac regulatory network.
    MeSH term(s) Amino Acid Sequence ; Animals ; Base Sequence ; Consensus Sequence ; DNA/chemistry ; Humans ; Mice ; Molecular Sequence Data ; Myocardium/metabolism ; Protein Stability ; Protein Structure, Tertiary ; T-Box Domain Proteins/chemistry
    Chemical Substances T-Box Domain Proteins ; TBX20 protein, human ; Tbx20 protein, mouse ; DNA (9007-49-2)
    Language English
    Publishing date 2009-06-12
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 80229-3
    ISSN 1089-8638 ; 0022-2836
    ISSN (online) 1089-8638
    ISSN 0022-2836
    DOI 10.1016/j.jmb.2009.04.056
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Two distinct Staufen isoforms in Xenopus are vegetally localized during oogenesis.

    Allison, Rachel / Czaplinski, Kevin / Git, Anna / Adegbenro, Elizabeth / Stennard, Fiona / Houliston, Evelyn / Standart, Nancy

    RNA (New York, N.Y.)

    2004  Volume 10, Issue 11, Page(s) 1751–1763

    Abstract: Localization of mRNA is an important way of generating early asymmetries in the developing embryo. In Drosophila, Staufen is intimately involved in the localization of maternally inherited mRNAs critical for cell fate determination in the embryo. We show ...

    Abstract Localization of mRNA is an important way of generating early asymmetries in the developing embryo. In Drosophila, Staufen is intimately involved in the localization of maternally inherited mRNAs critical for cell fate determination in the embryo. We show that double-stranded RNA-binding Staufen proteins are present in the oocytes of a vertebrate, Xenopus, and are localized to the vegetal cytoplasm, a region where important mRNAs including VegT and Vg1 mRNA become localized. We identified two Staufen isoforms named XStau1 and XStau2, where XStau1 was found to be the principal Staufen protein in oocytes, eggs, and embryos, the levels of both proteins peaking during mid-oogenesis. In adults, Xenopus Staufens are principally expressed in ovary and testis. XStau1 was detectable throughout the oocyte cytoplasm by immunofluorescence and was concentrated in the vegetal cortical region from stage II onward. It showed partial codistribution with subcortical endoplasmic reticulum (ER), raising the possibility that Staufen may anchor mRNAs to specific ER-rich domains. We further showed that XStau proteins are transiently phosphorylated by the MAPK pathway during meiotic maturation, a period during which RNAs such as Vg1 RNA are released from their tight localization at the vegetal cortex. These findings provide evidence that Staufen proteins are involved in targeting and/or anchoring of maternal determinants to the vegetal cortex of the oocyte in Xenopus. The Xenopus oocyte should thus provide a valuable system to dissect the role of Staufen proteins in RNA localization and vertebrate development.
    MeSH term(s) Amino Acid Sequence ; Animals ; Cell Polarity ; Cloning, Molecular ; Cytoplasm/metabolism ; Endoplasmic Reticulum/metabolism ; Female ; Fluorescent Antibody Technique, Direct ; Meiosis ; Microscopy, Confocal ; Mitogen-Activated Protein Kinases/metabolism ; Molecular Sequence Data ; Oocytes/cytology ; Oocytes/metabolism ; Oogenesis ; Phosphorylation ; Protein Isoforms/chemistry ; Protein Isoforms/genetics ; Protein Isoforms/metabolism ; Protein Structure, Tertiary ; RNA-Binding Proteins/chemistry ; RNA-Binding Proteins/genetics ; RNA-Binding Proteins/metabolism ; Sequence Analysis, Protein ; Sequence Homology, Amino Acid ; Xenopus ; Xenopus Proteins/chemistry ; Xenopus Proteins/genetics ; Xenopus Proteins/metabolism
    Chemical Substances Protein Isoforms ; RNA-Binding Proteins ; STAU1 protein, Xenopus ; Xenopus Proteins ; Mitogen-Activated Protein Kinases (EC 2.7.11.24)
    Language English
    Publishing date 2004-11
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, P.H.S.
    ZDB-ID 1241540-6
    ISSN 1355-8382
    ISSN 1355-8382
    DOI 10.1261/rna.7450204
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Eomesodermin is expressed in mouse oocytes and pre-implantation embryos.

    McConnell, Josie / Petrie, Linda / Stennard, Fiona / Ryan, Kenneth / Nichols, Jennifer

    Molecular reproduction and development

    2005  Volume 71, Issue 4, Page(s) 399–404

    Abstract: T-box genes are a highly conserved family of genes encoding transcription factors, which share a conserved DNA binding domain (the T-box). Appropriate temporal and spatial expression of this gene family is critical for gastrulation and organogenesis in a ...

    Abstract T-box genes are a highly conserved family of genes encoding transcription factors, which share a conserved DNA binding domain (the T-box). Appropriate temporal and spatial expression of this gene family is critical for gastrulation and organogenesis in a number of species. The T-box containing gene Eomesodermin was first identified in Xenopus, where it plays a critical role in mesoderm formation. In situ analyses in mice have described the expression patterns of the mouse ortholog of this gene mEomesodermin (mEomes) at the time of implantation and during fetal development. Additional studies involving the disruption of the mEomes gene, have demonstrated an additional role for mEomes in trophoblast formation. However, these analyses did not address the possibility that maternally encoded or pre-blastocyst zygotic transcription of mEomes may also contribute to embryonic development. We show here that mEomes mRNA is present prior to blastocyst formation, and that the protein product of mEomes is associated with nuclear DNA during oocyte development and persistently localizes within all nuclei of the preimplantation embryo until the early blastocyst stage. mEomes protein is associated with the meiotic spindle in the unfertilized egg and with the mitotic spindle at each cell division. Our results are consistent with mEomesodermin having a role in early preimplantation development and inner cell mass formation in addition to its function in the trophoblast lineage.
    MeSH term(s) Animals ; Blastocyst/metabolism ; Blotting, Western ; Cross Reactions ; Female ; Mice ; Microscopy, Confocal ; Oocytes/metabolism ; RNA, Messenger/metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; T-Box Domain Proteins/genetics ; T-Box Domain Proteins/immunology ; T-Box Domain Proteins/metabolism
    Chemical Substances Eomes protein, mouse ; RNA, Messenger ; T-Box Domain Proteins
    Language English
    Publishing date 2005-08
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 20321-x
    ISSN 1098-2795 ; 1040-452X
    ISSN (online) 1098-2795
    ISSN 1040-452X
    DOI 10.1002/mrd.20318
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: Cardiac T-box factor Tbx20 directly interacts with Nkx2-5, GATA4, and GATA5 in regulation of gene expression in the developing heart.

    Stennard, Fiona A / Costa, Mauro W / Elliott, David A / Rankin, Scott / Haast, Saskia J P / Lai, Donna / McDonald, Lachlan P A / Niederreither, Karen / Dolle, Pascal / Bruneau, Benoit G / Zorn, Aaron M / Harvey, Richard P

    Developmental biology

    2003  Volume 262, Issue 2, Page(s) 206–224

    Abstract: Tbx20 is a member of the T-box transcription factor family expressed in the forming hearts of vertebrate and invertebrate embryos. We report here analysis of Tbx20 expression during murine cardiac development and assessment of DNA-binding and ... ...

    Abstract Tbx20 is a member of the T-box transcription factor family expressed in the forming hearts of vertebrate and invertebrate embryos. We report here analysis of Tbx20 expression during murine cardiac development and assessment of DNA-binding and transcriptional properties of Tbx20 isoforms. Tbx20 was expressed in myocardium and endocardium, including high levels in endocardial cushions. cDNAs generated by alternative splicing encode at least four Tbx20 isoforms, and Tbx20a uniquely carried strong transactivation and transrepression domains in its C terminus. Isoforms with an intact T-box bound specifically to DNA sites resembling the consensus brachyury half site, although with less avidity compared with the related factor, Tbx5. Tbx20 physically interacted with cardiac transcription factors Nkx2-5, GATA4, and GATA5, collaborating to synergistically activate cardiac gene expression. Among cardiac GATA factors, there was preferential synergy with GATA5, implicated in endocardial differentiation. In Xenopus embryos, enforced expression of Tbx20a, but not Tbx20b, led to induction of mesodermal and endodermal lineage markers as well as cell migration, indicating that the long Tbx20a isoform uniquely bears functional domains that can alter gene expression and developmental behaviour in an in vivo context. We propose that Tbx20 plays an integrated role in the ancient myogenic program of the heart, and has been additionally coopted during evolution of vertebrates for endocardial cushion development.
    MeSH term(s) Alternative Splicing ; Animals ; DNA/metabolism ; DNA-Binding Proteins/metabolism ; GATA4 Transcription Factor ; GATA5 Transcription Factor ; Gene Expression Regulation, Developmental/physiology ; Heart/embryology ; Homeobox Protein Nkx-2.5 ; Homeodomain Proteins/metabolism ; Mice ; Mutation ; Protein Isoforms ; T-Box Domain Proteins/genetics ; T-Box Domain Proteins/metabolism ; Transcription Factors/metabolism ; Xenopus ; Xenopus Proteins/metabolism
    Chemical Substances DNA-Binding Proteins ; GATA-5a protein, Xenopus ; GATA-5b protein, Xenopus ; GATA4 Transcription Factor ; GATA4 protein, Xenopus ; GATA5 Transcription Factor ; Gata5 protein, mouse ; Homeobox Protein Nkx-2.5 ; Homeodomain Proteins ; NKX2-5 protein, Xenopus ; NKX2-5 protein, human ; Nkx2-5 protein, mouse ; Protein Isoforms ; T-Box Domain Proteins ; T-box transcription factor 5 ; Tbx20 protein, mouse ; Transcription Factors ; Xenopus Proteins ; DNA (9007-49-2)
    Language English
    Publishing date 2003-10-15
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, P.H.S.
    ZDB-ID 1114-9
    ISSN 1095-564X ; 0012-1606
    ISSN (online) 1095-564X
    ISSN 0012-1606
    DOI 10.1016/s0012-1606(03)00385-3
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Murine T-box transcription factor Tbx20 acts as a repressor during heart development, and is essential for adult heart integrity, function and adaptation.

    Stennard, Fiona A / Costa, Mauro W / Lai, Donna / Biben, Christine / Furtado, Milena B / Solloway, Mark J / McCulley, David J / Leimena, Christiana / Preis, Jost I / Dunwoodie, Sally L / Elliott, David E / Prall, Owen W J / Black, Brian L / Fatkin, Diane / Harvey, Richard P

    Development (Cambridge, England)

    2005  Volume 132, Issue 10, Page(s) 2451–2462

    Abstract: The genetic hierarchies guiding lineage specification and morphogenesis of the mammalian embryonic heart are poorly understood. We now show by gene targeting that murine T-box transcription factor Tbx20 plays a central role in these pathways, and has ... ...

    Abstract The genetic hierarchies guiding lineage specification and morphogenesis of the mammalian embryonic heart are poorly understood. We now show by gene targeting that murine T-box transcription factor Tbx20 plays a central role in these pathways, and has important activities in both cardiac development and adult function. Loss of Tbx20 results in death of embryos at mid-gestation with grossly abnormal heart morphogenesis. Underlying these disturbances was a severely compromised cardiac transcriptional program, defects in the molecular pre-pattern, reduced expansion of cardiac progenitors and a block to chamber differentiation. Notably, Tbx20-null embryos showed ectopic activation of Tbx2 across the whole heart myogenic field. Tbx2 encodes a transcriptional repressor normally expressed in non-chamber myocardium, and in the atrioventricular canal it has been proposed to inhibit chamber-specific gene expression through competition with positive factor Tbx5. Our data demonstrate a repressive activity for Tbx20 and place it upstream of Tbx2 in the cardiac genetic program. Thus, hierarchical, repressive interactions between Tbx20 and other T-box genes and factors underlie the primary lineage split into chamber and non-chamber myocardium in the forming heart, an early event upon which all subsequent morphogenesis depends. Additional roles for Tbx20 in adult heart integrity and contractile function were revealed by in-vivo cardiac functional analysis of Tbx20 heterozygous mutant mice. These data suggest that mutations in human cardiac transcription factor genes, possibly including TBX20, underlie both congenital heart disease and adult cardiomyopathies.
    MeSH term(s) Animals ; Blotting, Northern ; Cell Differentiation/physiology ; Echocardiography ; Gene Expression Regulation, Developmental ; Gene Targeting ; Heart/embryology ; Heart/physiology ; Histocytochemistry ; In Situ Hybridization ; In Situ Nick-End Labeling ; Mice/embryology ; Mice, Inbred C57BL ; Morphogenesis ; Mutation/genetics ; Myocardium/metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; T-Box Domain Proteins/genetics ; T-Box Domain Proteins/metabolism
    Chemical Substances T-Box Domain Proteins ; Tbx20 protein, mouse
    Language English
    Publishing date 2005-05
    Publishing country England
    Document type Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 90607-4
    ISSN 1477-9129 ; 0950-1991
    ISSN (online) 1477-9129
    ISSN 0950-1991
    DOI 10.1242/dev.01799
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: An Nkx2-5/Bmp2/Smad1 negative feedback loop controls heart progenitor specification and proliferation.

    Prall, Owen W J / Menon, Mary K / Solloway, Mark J / Watanabe, Yusuke / Zaffran, Stéphane / Bajolle, Fanny / Biben, Christine / McBride, Jim J / Robertson, Bronwyn R / Chaulet, Hervé / Stennard, Fiona A / Wise, Natalie / Schaft, Daniel / Wolstein, Orit / Furtado, Milena B / Shiratori, Hidetaka / Chien, Kenneth R / Hamada, Hiroshi / Black, Brian L /
    Saga, Yumiko / Robertson, Elizabeth J / Buckingham, Margaret E / Harvey, Richard P

    Cell

    2007  Volume 128, Issue 5, Page(s) 947–959

    Abstract: During heart development the second heart field (SHF) provides progenitor cells for most cardiomyocytes and expresses the homeodomain factor Nkx2-5. We now show that feedback repression of Bmp2/Smad1 signaling by Nkx2-5 critically regulates SHF ... ...

    Abstract During heart development the second heart field (SHF) provides progenitor cells for most cardiomyocytes and expresses the homeodomain factor Nkx2-5. We now show that feedback repression of Bmp2/Smad1 signaling by Nkx2-5 critically regulates SHF proliferation and outflow tract (OFT) morphology. In the cardiac fields of Nkx2-5 mutants, genes controlling cardiac specification (including Bmp2) and maintenance of the progenitor state were upregulated, leading initially to progenitor overspecification, but subsequently to failed SHF proliferation and OFT truncation. In Smad1 mutants, SHF proliferation and deployment to the OFT were increased, while Smad1 deletion in Nkx2-5 mutants rescued SHF proliferation and OFT development. In Nkx2-5 hypomorphic mice, which recapitulate human congenital heart disease (CHD), OFT anomalies were also rescued by Smad1 deletion. Our findings demonstrate that Nkx2-5 orchestrates the transition between periods of cardiac induction, progenitor proliferation, and OFT morphogenesis via a Smad1-dependent negative feedback loop, which may be a frequent molecular target in CHD.
    MeSH term(s) Animals ; Bone Morphogenetic Protein 2 ; Bone Morphogenetic Proteins/metabolism ; Cell Proliferation ; DNA, Complementary ; Embryo, Mammalian ; Feedback, Physiological ; Heart/embryology ; Heart Defects, Congenital/genetics ; Heart Defects, Congenital/metabolism ; Homeobox Protein Nkx-2.5 ; Homeodomain Proteins/genetics ; Homeodomain Proteins/metabolism ; Humans ; LIM-Homeodomain Proteins ; Mice ; Multipotent Stem Cells/cytology ; Multipotent Stem Cells/metabolism ; Myocardium/cytology ; Myocytes, Cardiac/cytology ; Myocytes, Cardiac/metabolism ; Oligonucleotide Array Sequence Analysis ; Phenotype ; Smad1 Protein/metabolism ; Transcription Factors/genetics ; Transcription Factors/metabolism ; Transforming Growth Factor beta/metabolism
    Chemical Substances BMP2 protein, human ; Bmp2 protein, mouse ; Bone Morphogenetic Protein 2 ; Bone Morphogenetic Proteins ; DNA, Complementary ; Homeobox Protein Nkx-2.5 ; Homeodomain Proteins ; LIM-Homeodomain Proteins ; Nkx2-5 protein, mouse ; Smad1 Protein ; Smad1 protein, mouse ; Transcription Factors ; Transforming Growth Factor beta ; insulin gene enhancer binding protein Isl-1
    Language English
    Publishing date 2007-03-09
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 187009-9
    ISSN 1097-4172 ; 0092-8674
    ISSN (online) 1097-4172
    ISSN 0092-8674
    DOI 10.1016/j.cell.2007.01.042
    Database MEDical Literature Analysis and Retrieval System OnLINE

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