LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 13

Search options

  1. Article ; Online: DNA hypomethylation activates Cdk4/6 and Atr to induce DNA replication and cell cycle arrest to constrain liver outgrowth in zebrafish.

    Madakashira, Bhavani P / Magnani, Elena / Ranjan, Shashi / Sadler, Kirsten C

    Nucleic acids research

    2024  Volume 52, Issue 6, Page(s) 3069–3087

    Abstract: Coordinating epigenomic inheritance and cell cycle progression is essential for organogenesis. UHRF1 connects these functions during development by facilitating maintenance of DNA methylation and cell cycle progression. Here, we provide evidence ... ...

    Abstract Coordinating epigenomic inheritance and cell cycle progression is essential for organogenesis. UHRF1 connects these functions during development by facilitating maintenance of DNA methylation and cell cycle progression. Here, we provide evidence resolving the paradoxical phenotype of uhrf1 mutant zebrafish embryos which have activation of pro-proliferative genes and increased number of hepatocytes in S-phase, but the liver fails to grow. We uncover decreased Cdkn2a/b and persistent Cdk4/6 activation as the mechanism driving uhrf1 mutant hepatocytes into S-phase. This induces replication stress, DNA damage and Atr activation. Palbociclib treatment of uhrf1 mutants prevented aberrant S-phase entry, reduced DNA damage, and rescued most cellular and developmental phenotypes, but it did not rescue DNA hypomethylation, transposon expression or the interferon response. Inhibiting Atr reduced DNA replication and increased liver size in uhrf1 mutants, suggesting that Atr activation leads to dormant origin firing and prevents hepatocyte proliferation. Cdkn2a/b was downregulated pro-proliferative genes were also induced in a Cdk4/6 dependent fashion in the liver of dnmt1 mutants, suggesting DNA hypomethylation as a mechanism of Cdk4/6 activation during development. This shows that the developmental defects caused by DNA hypomethylation are attributed to persistent Cdk4/6 activation, DNA replication stress, dormant origin firing and cell cycle inhibition.
    MeSH term(s) Animals ; Ataxia Telangiectasia Mutated Proteins/genetics ; Ataxia Telangiectasia Mutated Proteins/metabolism ; Cell Cycle/genetics ; Cell Cycle Checkpoints/genetics ; Cell Division/genetics ; Cyclin-Dependent Kinase 4/genetics ; Cyclin-Dependent Kinase 4/metabolism ; Cyclin-Dependent Kinase 6/genetics ; Cyclin-Dependent Kinase 6/metabolism ; DNA/metabolism ; DNA Methylation ; DNA Replication/genetics ; Embryo, Nonmammalian ; Liver/growth & development ; Liver/metabolism ; S Phase ; Zebrafish/genetics ; Zebrafish/metabolism ; Enzyme Activation/genetics
    Chemical Substances Ataxia Telangiectasia Mutated Proteins (EC 2.7.11.1) ; ATR protein, zebrafish (EC 2.7.11.1) ; Cyclin-Dependent Kinase 4 (EC 2.7.11.22) ; Cyclin-Dependent Kinase 6 (EC 2.7.11.22) ; DNA (9007-49-2)
    Language English
    Publishing date 2024-02-06
    Publishing country England
    Document type Journal Article
    ZDB-ID 186809-3
    ISSN 1362-4962 ; 1362-4954 ; 0301-5610 ; 0305-1048
    ISSN (online) 1362-4962 ; 1362-4954
    ISSN 0301-5610 ; 0305-1048
    DOI 10.1093/nar/gkae031
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article: Nuclear Organization during Hepatogenesis in Zebrafish Requires Uhrf1

    Madakashira, Bhavani P. / Zhang, Chi / Macchi, Filippo / Magnani, Elena / Sadler, Kirsten C.

    Genes. 2021 July 16, v. 12, no. 7

    2021  

    Abstract: Acquisition of cellular fate during development is initiated and maintained by well-coordinated patterns of gene expression that are dictated by the epigenetic landscape and genome organization in the nucleus. While the epigenetic marks that mediate ... ...

    Abstract Acquisition of cellular fate during development is initiated and maintained by well-coordinated patterns of gene expression that are dictated by the epigenetic landscape and genome organization in the nucleus. While the epigenetic marks that mediate developmental gene expression patterns during organogenesis have been well studied, less is known about how epigenetic marks influence nuclear organization during development. This study examines the relationship between nuclear structure, chromatin accessibility, DNA methylation, and gene expression during hepatic outgrowth in zebrafish larvae. We investigate the relationship between these features using mutants that lack DNA methylation. Hepatocyte nuclear morphology was established coincident with hepatocyte differentiation at 80 h post-fertilization (hpf), and nuclear shape and size continued to change until the conclusion of outgrowth and morphogenesis at 120 hpf. Integrating ATAC-Seq analysis with DNA methylation profiling of zebrafish livers at 120 hpf showed that closed and highly methylated chromatin occupies most transposable elements and that open chromatin correlated with gene expression. DNA hypomethylation, due to mutation of genes encoding ubiquitin-like, containing PHD and RING Finger Domains 1 (uhrf1) and DNA methyltransferase (dnmt1), did not block hepatocyte differentiation, but had dramatic effects on nuclear organization. Hepatocytes in uhrf1 mutants have large, deformed nuclei with multiple nucleoli, downregulation of nucleolar genes, and a complete lack of the nuclear lamina. Loss of lamin B2 staining was phenocopied by dnmt1 mutation. Together, these data show that hepatocyte nuclear morphogenesis coincides with organ morphogenesis and outgrowth, and that DNA methylation directs chromatin organization, and, in turn, hepatocyte nuclear shape and size during liver development.
    Keywords DNA hypomethylation ; DNA methyltransferase ; Danio rerio ; RING finger domains ; chromatin ; epigenetics ; gene expression ; hepatocytes ; liver ; mutation ; nuclear lamina ; organogenesis
    Language English
    Dates of publication 2021-0716
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article
    ZDB-ID 2527218-4
    ISSN 2073-4425
    ISSN 2073-4425
    DOI 10.3390/genes12071081
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

  3. Article: DNA Methylation, Nuclear Organization, and Cancer.

    Madakashira, Bhavani P / Sadler, Kirsten C

    Frontiers in genetics

    2017  Volume 8, Page(s) 76

    Abstract: The dramatic re-organization of the cancer cell nucleus creates telltale morphological features critical for pathological staging of tumors. In addition, the changes to the mutational and epigenetic landscape in cancer cells alter the structure and ... ...

    Abstract The dramatic re-organization of the cancer cell nucleus creates telltale morphological features critical for pathological staging of tumors. In addition, the changes to the mutational and epigenetic landscape in cancer cells alter the structure and stability of the genome and directly contribute to malignancy. DNA methylation is one of the best studied epigenetic changes in cancer, as nearly every type of cancer studied shows a loss of DNA methylation spread across most of the genome. This global hypomethylation is accompanied by hypermethylation at distinct loci, and much of the work on DNA methylation in cancer has focused on how local changes contribute to gene expression. However, the emerging picture is that the changes to DNA methylation in cancer cells has little direct effect on gene expression but instead impacts the organization of the genome in the nucleus. Several recent studies that take a broad view of the cancer epigenome find that the most profound changes to the cancer methylome are spread across large segments of the genome, and that the focal changes are reflective of a whole reorganization of epigenome. Hallmarks of nuclear reorganization in cancer are found in the long regions of chromatin marked by histone methylation (LOCKs) and nuclear lamina interactions (LADs). In this review, we focus on a novel perspective that DNA methylation changes in cancer impact the global structure of heterochromatin, LADs and LOCKs, and how these global changes, in turn, contribute to gene expression changes and genomic stability.
    Language English
    Publishing date 2017-06-07
    Publishing country Switzerland
    Document type Journal Article ; Review
    ZDB-ID 2606823-0
    ISSN 1664-8021
    ISSN 1664-8021
    DOI 10.3389/fgene.2017.00076
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  4. Article ; Online: Nuclear Organization during Hepatogenesis in Zebrafish Requires Uhrf1.

    Madakashira, Bhavani P / Zhang, Chi / Macchi, Filippo / Magnani, Elena / Sadler, Kirsten C

    Genes

    2021  Volume 12, Issue 7

    Abstract: Acquisition of cellular fate during development is initiated and maintained by well-coordinated patterns of gene expression that are dictated by the epigenetic landscape and genome organization in the nucleus. While the epigenetic marks that mediate ... ...

    Abstract Acquisition of cellular fate during development is initiated and maintained by well-coordinated patterns of gene expression that are dictated by the epigenetic landscape and genome organization in the nucleus. While the epigenetic marks that mediate developmental gene expression patterns during organogenesis have been well studied, less is known about how epigenetic marks influence nuclear organization during development. This study examines the relationship between nuclear structure, chromatin accessibility, DNA methylation, and gene expression during hepatic outgrowth in zebrafish larvae. We investigate the relationship between these features using mutants that lack DNA methylation. Hepatocyte nuclear morphology was established coincident with hepatocyte differentiation at 80 h post-fertilization (hpf), and nuclear shape and size continued to change until the conclusion of outgrowth and morphogenesis at 120 hpf. Integrating ATAC-Seq analysis with DNA methylation profiling of zebrafish livers at 120 hpf showed that closed and highly methylated chromatin occupies most transposable elements and that open chromatin correlated with gene expression. DNA hypomethylation, due to mutation of genes encoding ubiquitin-like, containing PHD and RING Finger Domains 1 (
    MeSH term(s) Animals ; Cell Differentiation/genetics ; Cell Nucleus/genetics ; Chromatin/metabolism ; Chromatin Assembly and Disassembly/genetics ; DNA (Cytosine-5-)-Methyltransferase 1/metabolism ; DNA Methylation/genetics ; Epigenesis, Genetic/genetics ; Gene Expression/genetics ; Hepatocytes/metabolism ; Larva/genetics ; Liver/embryology ; Liver/metabolism ; Organogenesis/genetics ; Trans-Activators/genetics ; Trans-Activators/metabolism ; Trans-Activators/physiology ; Zebrafish/metabolism ; Zebrafish Proteins/genetics ; Zebrafish Proteins/metabolism ; Zebrafish Proteins/physiology
    Chemical Substances Chromatin ; Trans-Activators ; Uhrf1 protein, zebrafish ; Zebrafish Proteins ; DNA (Cytosine-5-)-Methyltransferase 1 (EC 2.1.1.37) ; Dnmt1 protein, zebrafish (EC 2.1.1.37)
    Language English
    Publishing date 2021-07-16
    Publishing country Switzerland
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2527218-4
    ISSN 2073-4425 ; 2073-4425
    ISSN (online) 2073-4425
    ISSN 2073-4425
    DOI 10.3390/genes12071081
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  5. Article ; Online: uhrf1

    Magnani, Elena / Macchi, Filippo / Madakashira, Bhavani P / Zhang, Chi / Alaydaroos, Fatima / Sadler, Kirsten C

    Frontiers in immunology

    2021  Volume 12, Page(s) 627926

    Abstract: Activation of transposable elements (TEs) can cause cellular damage. Cytoplasmic nucleic acid sensing pathways evolved to detect pathogens, but can also serve to cull cells with inappropriate TE activation as TEs can be viral mimetics. Epigenetic ... ...

    Abstract Activation of transposable elements (TEs) can cause cellular damage. Cytoplasmic nucleic acid sensing pathways evolved to detect pathogens, but can also serve to cull cells with inappropriate TE activation as TEs can be viral mimetics. Epigenetic silencing of TEs is mediated in part by DNA methylation, but it is not clear if TE activation or the immune system contribute to the cellular damage caused by loss of DNA methylation. Here, we provide mechanistic insight into the observation of an activated interferon response in the liver of zebrafish larvae with deletion in critical components of the DNA methylation machinery,
    MeSH term(s) Adaptor Proteins, Signal Transducing/genetics ; Adaptor Proteins, Signal Transducing/metabolism ; Animals ; Animals, Genetically Modified ; DNA (Cytosine-5-)-Methyltransferase 1/deficiency ; DNA (Cytosine-5-)-Methyltransferase 1/genetics ; DNA (Cytosine-5-)-Methyltransferase 1/immunology ; DNA Methylation ; DNA Transposable Elements ; Epigenesis, Genetic ; Host-Pathogen Interactions ; Immunity/genetics ; Liver/embryology ; Liver/enzymology ; Liver/immunology ; Membrane Proteins/genetics ; Membrane Proteins/metabolism ; Molecular Mimicry ; Retroelements ; Trans-Activators/deficiency ; Trans-Activators/genetics ; Trans-Activators/immunology ; Tumor Necrosis Factor-alpha/genetics ; Tumor Necrosis Factor-alpha/metabolism ; Viruses/immunology ; Viruses/pathogenicity ; Zebrafish/embryology ; Zebrafish/genetics ; Zebrafish/immunology ; Zebrafish/metabolism ; Zebrafish Proteins/deficiency ; Zebrafish Proteins/genetics ; Zebrafish Proteins/immunology ; Zebrafish Proteins/metabolism
    Chemical Substances Adaptor Proteins, Signal Transducing ; DNA Transposable Elements ; MAVS protein, zebrafish ; Membrane Proteins ; Retroelements ; Trans-Activators ; Tumor Necrosis Factor-alpha ; Uhrf1 protein, zebrafish ; Zebrafish Proteins ; tmem173 protein, zebrafish ; DNA (Cytosine-5-)-Methyltransferase 1 (EC 2.1.1.37) ; Dnmt1 protein, zebrafish (EC 2.1.1.37)
    Language English
    Publishing date 2021-03-29
    Publishing country Switzerland
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2606827-8
    ISSN 1664-3224 ; 1664-3224
    ISSN (online) 1664-3224
    ISSN 1664-3224
    DOI 10.3389/fimmu.2021.627926
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  6. Article ; Online: Loss of DNA methylation in zebrafish embryos activates retrotransposons to trigger antiviral signaling.

    Chernyavskaya, Yelena / Mudbhary, Raksha / Zhang, Chi / Tokarz, Debra / Jacob, Vinitha / Gopinath, Smita / Sun, Xiaochen / Wang, Shuang / Magnani, Elena / Madakashira, Bhavani P / Yoder, Jeffrey A / Hoshida, Yujin / Sadler, Kirsten C

    Development (Cambridge, England)

    2017  Volume 144, Issue 16, Page(s) 2925–2939

    Abstract: Complex cytoplasmic nucleotide-sensing mechanisms can recognize foreign DNA based on a lack of methylation and initiate an immune response to clear the infection. Zebrafish embryos with global DNA hypomethylation caused by mutations in ... ...

    Abstract Complex cytoplasmic nucleotide-sensing mechanisms can recognize foreign DNA based on a lack of methylation and initiate an immune response to clear the infection. Zebrafish embryos with global DNA hypomethylation caused by mutations in the
    MeSH term(s) Animals ; DNA (Cytosine-5-)-Methyltransferase 1 ; DNA (Cytosine-5-)-Methyltransferases/genetics ; DNA (Cytosine-5-)-Methyltransferases/metabolism ; DNA Methylation/genetics ; DNA Methylation/physiology ; Retroelements/genetics ; Signal Transduction/genetics ; Signal Transduction/physiology ; Trans-Activators/genetics ; Trans-Activators/metabolism ; Zebrafish/embryology ; Zebrafish/metabolism ; Zebrafish Proteins/genetics ; Zebrafish Proteins/metabolism
    Chemical Substances Retroelements ; Trans-Activators ; Uhrf1 protein, zebrafish ; Zebrafish Proteins ; DNA (Cytosine-5-)-Methyltransferase 1 (EC 2.1.1.37) ; DNA (Cytosine-5-)-Methyltransferases (EC 2.1.1.37) ; Dnmt1 protein, zebrafish (EC 2.1.1.37)
    Language English
    Publishing date 2017-07-11
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; 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.147629
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  7. Article ; Online: Variant Histone H2afv reprograms DNA methylation during early zebrafish development.

    Madakashira, Bhavani / Corbett, Laura / Zhang, Chi / Paoli, Pier / Casement, John W / Mann, Jelena / Sadler, Kirsten C / Mann, Derek A

    Epigenetics

    2017  Volume 12, Issue 9, Page(s) 811–824

    Abstract: The DNA methylome is re-patterned during discrete phases of vertebrate development. In zebrafish, there are 2 waves of global DNA demethylation and re-methylation: the first occurs before gastrulation when the parental methylome is changed to the zygotic ...

    Abstract The DNA methylome is re-patterned during discrete phases of vertebrate development. In zebrafish, there are 2 waves of global DNA demethylation and re-methylation: the first occurs before gastrulation when the parental methylome is changed to the zygotic pattern and the second occurs after formation of the embryonic body axis, during organ specification. The occupancy of the histone variant H2A.Z and regions of DNA methylation are generally anti-correlated, and it has been proposed that H2A.Z restricts the boundaries of highly methylated regions. While many studies have described the dynamics of methylome changes during early zebrafish development, the factors involved in establishing the DNA methylation landscape in zebrafish embryos have not been identified. We test the hypothesis that the zebrafish ortholog of H2A.Z (H2afv) restricts DNA methylation during development. We find that, in control embryos, bulk genome methylation decreases after gastrulation, with a nadir at the bud stage, and peaks during mid-somitogenesis; by 24 hours post -fertilization, total DNA methylation levels return to those detected in gastrula. Early zebrafish embryos depleted of H2afv have significantly more bulk DNA methylation during somitogenesis, suggesting that H2afv limits methylation during this stage of development. H2afv deficient embryos are small, with multisystemic abnormalities. Genetic interaction experiments demonstrate that these phenotypes are suppressed by depletion of DNA methyltransferase 1 (Dnmt1). This work demonstrates that H2afv is essential for global DNA methylation reprogramming during early vertebrate development and that embryonic development requires crosstalk between H2afv and Dnmt1.
    MeSH term(s) Animals ; DNA (Cytosine-5-)-Methyltransferase 1/genetics ; DNA (Cytosine-5-)-Methyltransferase 1/physiology ; DNA Methylation ; Genetic Variation ; Histones/metabolism ; Phenotype ; Zebrafish/embryology ; Zebrafish/genetics ; Zebrafish/growth & development ; Zebrafish Proteins/genetics ; Zebrafish Proteins/physiology
    Chemical Substances Histones ; Zebrafish Proteins ; DNA (Cytosine-5-)-Methyltransferase 1 (EC 2.1.1.37) ; Dnmt1 protein, zebrafish (EC 2.1.1.37)
    Language English
    Publishing date 2017-11-24
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ISSN 1559-2308
    ISSN (online) 1559-2308
    DOI 10.1080/15592294.2017.1359382
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  8. Article ; Online: The function of FGF signaling in the lens placode.

    Garcia, Claudia M / Huang, Jie / Madakashira, Bhavani P / Liu, Ying / Rajagopal, Ramya / Dattilo, Lisa / Robinson, Michael L / Beebe, David C

    Developmental biology

    2011  Volume 351, Issue 1, Page(s) 176–185

    Abstract: Previous studies suggested that FGF signaling is important for lens formation. However, the times at which FGFs act to promote lens formation, the FGFs that are involved, the cells that secrete them and the mechanisms by which FGF signaling may promote ... ...

    Abstract Previous studies suggested that FGF signaling is important for lens formation. However, the times at which FGFs act to promote lens formation, the FGFs that are involved, the cells that secrete them and the mechanisms by which FGF signaling may promote lens formation are not known. We found that transcripts encoding several FGF ligands and the four classical FGF receptors are detectable in the lens-forming ectoderm at the time of lens induction. Conditional deletion of Fgfr1 and Fgfr2 from this tissue resulted in the formation of small lens rudiments that soon degenerated. Lens placodes lacking Fgfr1 and 2 were thinner than in wild-type embryos. Deletion of Fgfr2 increased cell death from the initiation of placode formation and concurrent deletion of Fgfr1 enhanced this phenotype. Fgfr1/2 conditional knockout placode cells expressed lower levels of proteins known to be regulated by FGF receptor signaling, but proteins known to be important for lens formation were present at normal levels in the remaining placode cells, including the transcription factors Pax6, Sox2 and FoxE3 and the lens-preferred protein αA-crystallin. Previous studies identified a genetic interaction between BMP and FGF signaling in lens formation and conditional deletion of Bmpr1a caused increased cell death in the lens placode, resulting in the formation of smaller lenses. In the present study, conditional deletion of both Bmpr1a and Fgfr2 increased cell death beyond that seen in Fgfr2(CKO) placodes and prevented lens formation. These results suggest that the primary role of autocrine or paracrine FGF signaling is to provide essential survival signals to lens placode cells. Because apoptosis was already increased at the onset of placode formation in Fgfr1/2 conditional knockout placode cells, FGF signaling was functionally absent during the period of lens induction by the optic vesicle. Since the expression of proteins required for lens formation was not altered in the knockout placode cells, we can conclude that FGF signaling from the optic vesicle is not required for lens induction.
    MeSH term(s) Animals ; Bone Morphogenetic Protein Receptors/physiology ; Ectoderm/chemistry ; Eye Proteins/physiology ; Fibroblast Growth Factors/analysis ; Fibroblast Growth Factors/physiology ; Germ-Line Mutation ; Homeodomain Proteins/physiology ; Lens, Crystalline/embryology ; Mice ; PAX6 Transcription Factor ; Paired Box Transcription Factors/physiology ; Receptors, Fibroblast Growth Factor/analysis ; Repressor Proteins/physiology ; Signal Transduction/physiology
    Chemical Substances Eye Proteins ; Homeodomain Proteins ; PAX6 Transcription Factor ; Paired Box Transcription Factors ; Pax6 protein, mouse ; Receptors, Fibroblast Growth Factor ; Repressor Proteins ; Fibroblast Growth Factors (62031-54-3) ; Bone Morphogenetic Protein Receptors (EC 2.7.11.30)
    Language English
    Publishing date 2011-01-09
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 1114-9
    ISSN 1095-564X ; 0012-1606
    ISSN (online) 1095-564X
    ISSN 0012-1606
    DOI 10.1016/j.ydbio.2011.01.001
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  9. Article ; Online: Sef is a negative regulator of fiber cell differentiation in the ocular lens.

    Newitt, Peter / Boros, Jessica / Madakashira, Bhavani P / Robinson, Michael L / Reneker, Lixing W / McAvoy, John W / Lovicu, Frank J

    Differentiation; research in biological diversity

    2010  Volume 80, Issue 1, Page(s) 53–67

    Abstract: Growth factor signaling, mediated via receptor tyrosine kinases (RTKs), needs to be tightly regulated in many developmental systems to ensure a physiologically appropriate biological outcome. At one level this regulation may involve spatially and ... ...

    Abstract Growth factor signaling, mediated via receptor tyrosine kinases (RTKs), needs to be tightly regulated in many developmental systems to ensure a physiologically appropriate biological outcome. At one level this regulation may involve spatially and temporally ordered patterns of expression of specific RTK signaling antagonists, such as Sef (similar expression to fgfs). Growth factors, notably FGFs, play important roles in development of the vertebrate ocular lens. FGF induces lens cell proliferation and differentiation at progressively higher concentrations and there is compelling evidence that a gradient of FGF signaling in the eye determines lens polarity and growth patterns. We have recently identified the presence of Sef in the lens, with strongest expression in the epithelial cells. Given the important role for FGFs in lens developmental biology, we employed transgenic mouse strategies to determine if Sef could be involved in regulating lens cell behaviour. Over-expressing Sef specifically in the lens of transgenic mice led to impaired lens and eye development that resulted in microphthalmia. Sef inhibited primary lens fiber cell elongation and differentiation, as well as increased apoptosis, consistent with a block in FGFR-mediated signaling during lens morphogenesis. These results are consistent with growth factor antagonists, such as Sef, being important negative regulators of growth factor signaling. Moreover, the lens provides a useful paradigm as to how opposing gradients of a growth factor and its antagonist could work together to determine and stabilise tissue patterning during development and growth.
    MeSH term(s) Animals ; Apoptosis ; Blotting, Western ; Cell Differentiation ; Embryo, Mammalian/cytology ; Embryo, Mammalian/metabolism ; Epithelial Cells/metabolism ; Female ; Fibroblast Growth Factors/genetics ; Fibroblast Growth Factors/metabolism ; Humans ; In Situ Nick-End Labeling ; Lens, Crystalline/cytology ; Lens, Crystalline/metabolism ; Male ; Membrane Proteins/physiology ; Mice ; Mice, Transgenic ; Microphthalmos/metabolism ; Microphthalmos/pathology ; Promoter Regions, Genetic ; RNA, Messenger/genetics ; Receptors, Fibroblast Growth Factor/physiology ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; alpha-Crystallin A Chain/genetics
    Chemical Substances Membrane Proteins ; RNA, Messenger ; Receptors, Fibroblast Growth Factor ; Sef protein, mouse ; alpha-Crystallin A Chain ; Fibroblast Growth Factors (62031-54-3)
    Language English
    Publishing date 2010-06-09
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 184540-8
    ISSN 1432-0436 ; 0301-4681
    ISSN (online) 1432-0436
    ISSN 0301-4681
    DOI 10.1016/j.diff.2010.05.005
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  10. Article ; Online: Frs2α enhances fibroblast growth factor-mediated survival and differentiation in lens development.

    Madakashira, Bhavani P / Kobrinski, Daniel A / Hancher, Andrew D / Arneman, Elizabeth C / Wagner, Brad D / Wang, Fen / Shin, Hailey / Lovicu, Frank J / Reneker, Lixing W / Robinson, Michael L

    Development (Cambridge, England)

    2012  Volume 139, Issue 24, Page(s) 4601–4612

    Abstract: Most growth factor receptor tyrosine kinases (RTKs) signal through similar intracellular pathways, but they often have divergent biological effects. Therefore, elucidating the mechanism of channeling the intracellular effect of RTK stimulation to ... ...

    Abstract Most growth factor receptor tyrosine kinases (RTKs) signal through similar intracellular pathways, but they often have divergent biological effects. Therefore, elucidating the mechanism of channeling the intracellular effect of RTK stimulation to facilitate specific biological responses represents a fundamental biological challenge. Lens epithelial cells express numerous RTKs with the ability to initiate the phosphorylation (activation) of Erk1/2 and PI3-K/Akt signaling. However, only Fgfr stimulation leads to lens fiber cell differentiation in the developing mammalian embryo. Additionally, within the lens, only Fgfrs activate the signal transduction molecule Frs2α. Loss of Frs2α in the lens significantly increases apoptosis and decreases phosphorylation of both Erk1/2 and Akt. Also, Frs2α deficiency decreases the expression of several proteins characteristic of lens fiber cell differentiation, including Prox1, p57(KIP2), aquaporin 0 and β-crystallins. Although not normally expressed in the lens, the RTK TrkC phosphorylates Frs2α in response to binding the ligand NT3. Transgenic lens epithelial cells expressing both TrkC and NT3 exhibit several features characteristic of lens fiber cells. These include elongation, increased Erk1/2 and Akt phosphorylation, and the expression of β-crystallins. All these characteristics of NT3-TrkC transgenic lens epithelial cells depend on Frs2α. Therefore, tyrosine phosphorylation of Frs2α mediates Fgfr-dependent lens cell survival and provides a mechanistic basis for the unique fiber-differentiating capacity of Fgfs on mammalian lens epithelial cells.
    MeSH term(s) Animals ; Animals, Newborn ; Cell Differentiation/drug effects ; Cell Differentiation/genetics ; Cell Survival/drug effects ; Cell Survival/genetics ; Drug Synergism ; Embryo, Mammalian ; Fibroblast Growth Factors/pharmacology ; Fibroblast Growth Factors/physiology ; Lens, Crystalline/embryology ; Lens, Crystalline/growth & development ; Lens, Crystalline/metabolism ; Membrane Proteins/genetics ; Membrane Proteins/metabolism ; Membrane Proteins/physiology ; Mice ; Mice, Transgenic ; Morphogenesis/drug effects ; Morphogenesis/genetics ; Morphogenesis/physiology ; Rats ; Rats, Wistar ; Receptor, Fibroblast Growth Factor, Type 2/genetics ; Receptor, Fibroblast Growth Factor, Type 2/metabolism ; Receptor, Fibroblast Growth Factor, Type 2/physiology ; Receptor, trkC/genetics ; Receptor, trkC/metabolism ; Receptor, trkC/physiology ; Up-Regulation/genetics
    Chemical Substances FRS2alpha protein, mouse ; Membrane Proteins ; Fibroblast Growth Factors (62031-54-3) ; Fgfr2 protein, mouse (EC 2.7.10.1) ; Receptor, Fibroblast Growth Factor, Type 2 (EC 2.7.10.1) ; Receptor, trkC (EC 2.7.10.1)
    Language English
    Publishing date 2012-11-07
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 90607-4
    ISSN 1477-9129 ; 0950-1991
    ISSN (online) 1477-9129
    ISSN 0950-1991
    DOI 10.1242/dev.081737
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top