title: Interaction of the IP3-Ca2+ and MAPK signaling systems in the Xenopus blastomere: a possible frequency encoding mechanism for the control of the Xbra gene expression.
abstract: The intense periodic calcium activity experimentally observed in the Xenopus embryo at the Mid Blastula Transition stage is closely related to the competence of the embryonic cells of the marginal zone to respond to the posterior-mesodermal inducting signals from the Fibroblast Growth Factor (FGF). In this work we do a stability analysis and study numerically an extension of a mathematical model previously introduced by us [Diaz, J., Baier, G., Martinez-Mekler, G., Pastor, N., 2002. Interaction of the IP(3)-Ca(2+) and the FGF-MAPK signaling pathways in the Xenopus laevis embryo: a qualitative approach to the mesodermal induction problem. Biophys. Chem. 97, 55-72] for the interaction of the Inositol 1,4,5-triphosphate-Calcium (IP(3)-Ca(2+)) and the Mitogen-Activated Protein Kinase (MAPK) signaling pathways at the Mid Blastula Transition stage or stage 8 of development. This allows us to consider the effect of the oscillatory calcium dynamics on the FGF input signal carried by the MAP kinase (ERK) into the nucleus. We find that this interaction of the pathways induces a limit cycle behavior for ERK with frequency-encoding characteristics. We believe that this periodic increase of the ERK levels in the nucleus is related to the ability of the cell to express posteriorizing mesodermal features induced by the FGF signal at stage 8.
authors.affiliation: Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Col. Chamilpa, Cuernavaca, Morelos, Mexico. jdiaz@fis.unam.mx
authors.forename: José
authors.initials: J
authors.lastname: Díaz
authors.forename: Gustavo
authors.initials: G
authors.lastname: Martínez-Mekler
mesh_terms: D000465:Algorithms; D000818:Animals; D001757:Blastomeres / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology; D020013:Calcium Signaling / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D015544:Inositol 1,4,5-Trisphosphate / Q000502:physiology*; D053496:Inositol 1,4,5-Trisphosphate Receptors; D020935:MAP Kinase Signaling System / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008954:Models, Biological; D018160:Receptors, Cytoplasmic and Nuclear / Q000502:physiology; D017468:Receptors, Fibroblast Growth Factor / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D020825:T-Box Domain Proteins / Q000235:genetics; D029867:Xenopus Proteins / Q000235:genetics; D014982:Xenopus laevis; D048490:raf Kinases / Q000502:physiology
chemical_list: D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D017468:Receptors, Fibroblast Growth Factor; D020825:T-Box Domain Proteins; C116765:TBXT protein, Xenopus; D029867:Xenopus Proteins; D015544:Inositol 1,4,5-Trisphosphate; D048490:raf Kinases; D020928:Mitogen-Activated Protein Kinases; D002118:Calcium