The Experts below are selected from a list of 11616 Experts worldwide ranked by ideXlab platform
Andrée. Van Loon - One of the best experts on this subject based on the ideXlab platform.
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cyclin a cyclin b and Stringlike are regulated separately in cell cycle arrested trochoblasts of patella vulgata embryos
Development Genes and Evolution, 1998Co-Authors: Annemieke Van Der Kooij, Christiaan P W M Veraart, Andrée. Van LoonAbstract:Trochoblasts are the first cells to differentiate during the development of spiralian embryos. Differentiation is accompanied by a cell division arrest. In embryos of the limpet Patella vulgata, the participation of cell cycle-regulating factors in trochoblast arrest was analysed as a first step to unravel its cause. We determined the cell cycle phase in which the trochoblasts are arrested by analysing the subcellular locations of mitotic cyclins. The results show that the trochoblasts are most likely arrested in the G2 phase. This was supported by measurement of the DNA content in trochoblast nuclei after the last division. Trochoblasts complete their final division at the sixth mitotic cycle. This mitotic cycle resembles the first postblastoderm cell cycle of Drosophila, in which mitotic activity is controlled by Expression of the String gene. As failure of String Expression results in cell cycle arrest in the G2 phase, negative regulation of a PatellaString homolog could be responsible for trochoblast arrest. Although Stl messengers disappeared from trochoblasts during their final division, Expression was observed again 20 min later. Messengers remained present in all trochoblasts at low levels during further development. Thus, Expression of the Stringlike gene allows the cell cycle arrest of these cells, whereas in Drosophila cells arrested in division lack String messengers.
Annemieke Van Der Kooij - One of the best experts on this subject based on the ideXlab platform.
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cyclin a cyclin b and Stringlike are regulated separately in cell cycle arrested trochoblasts of patella vulgata embryos
Development Genes and Evolution, 1998Co-Authors: Annemieke Van Der Kooij, Christiaan P W M Veraart, Andrée. Van LoonAbstract:Trochoblasts are the first cells to differentiate during the development of spiralian embryos. Differentiation is accompanied by a cell division arrest. In embryos of the limpet Patella vulgata, the participation of cell cycle-regulating factors in trochoblast arrest was analysed as a first step to unravel its cause. We determined the cell cycle phase in which the trochoblasts are arrested by analysing the subcellular locations of mitotic cyclins. The results show that the trochoblasts are most likely arrested in the G2 phase. This was supported by measurement of the DNA content in trochoblast nuclei after the last division. Trochoblasts complete their final division at the sixth mitotic cycle. This mitotic cycle resembles the first postblastoderm cell cycle of Drosophila, in which mitotic activity is controlled by Expression of the String gene. As failure of String Expression results in cell cycle arrest in the G2 phase, negative regulation of a PatellaString homolog could be responsible for trochoblast arrest. Although Stl messengers disappeared from trochoblasts during their final division, Expression was observed again 20 min later. Messengers remained present in all trochoblasts at low levels during further development. Thus, Expression of the Stringlike gene allows the cell cycle arrest of these cells, whereas in Drosophila cells arrested in division lack String messengers.
Christiaan P W M Veraart - One of the best experts on this subject based on the ideXlab platform.
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cyclin a cyclin b and Stringlike are regulated separately in cell cycle arrested trochoblasts of patella vulgata embryos
Development Genes and Evolution, 1998Co-Authors: Annemieke Van Der Kooij, Christiaan P W M Veraart, Andrée. Van LoonAbstract:Trochoblasts are the first cells to differentiate during the development of spiralian embryos. Differentiation is accompanied by a cell division arrest. In embryos of the limpet Patella vulgata, the participation of cell cycle-regulating factors in trochoblast arrest was analysed as a first step to unravel its cause. We determined the cell cycle phase in which the trochoblasts are arrested by analysing the subcellular locations of mitotic cyclins. The results show that the trochoblasts are most likely arrested in the G2 phase. This was supported by measurement of the DNA content in trochoblast nuclei after the last division. Trochoblasts complete their final division at the sixth mitotic cycle. This mitotic cycle resembles the first postblastoderm cell cycle of Drosophila, in which mitotic activity is controlled by Expression of the String gene. As failure of String Expression results in cell cycle arrest in the G2 phase, negative regulation of a PatellaString homolog could be responsible for trochoblast arrest. Although Stl messengers disappeared from trochoblasts during their final division, Expression was observed again 20 min later. Messengers remained present in all trochoblasts at low levels during further development. Thus, Expression of the Stringlike gene allows the cell cycle arrest of these cells, whereas in Drosophila cells arrested in division lack String messengers.
Hannele Ruoholabaker - One of the best experts on this subject based on the ideXlab platform.
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notch delta signaling induces a transition from mitotic cell cycle to endocycle in drosophila follicle cells
Development, 2001Co-Authors: Wumin Deng, Cassandra Althauser, Hannele RuoholabakerAbstract:In many developmental processes, polyploid cells are generated by a variation of the normal cell cycle called the endocycle in which cells increase their genomic content without dividing. How the transition from the normal mitotic cycle to endocycle is regulated is poorly understood. We show that the transition from mitotic cycle to endocycle in the Drosophila follicle cell epithelium is regulated by the Notch pathway. Loss of Notch function in follicle cells or its ligand Delta function in the underlying germline disrupts the normal transition of the follicle cells from mitotic cycle to endocycle, mitotic cycling continues, leading to overproliferation of these cells. The regulation is at the transcriptional level, as Su(H), a downstream transcription factor in the pathway, is also required cell autonomously in follicle cells for proper transitioning to the endocycle. One target of Notch and Su(H) is likely to be the G2/M cell cycle regulator String, a phosphatase that activates Cdc2 by dephosphorylation. String is normally repressed in the follicle cells just before the endocycle transition, but is expressed when Notch is inactivated. Analysis of the activity of String enhancer elements in follicle cells reveals the presence of an element that promotes Expression of String until just before the onset of polyploidy in wild-type follicle cells but well beyond this stage in Notch mutant follicle cells. This suggests that it may be the target of the endocycle promoting activity of the Notch pathway. A second element that is insensitive to Notch regulation promotes String Expression earlier in follicle cell development, which explains why Notch, while active at both stages, represses String only at the mitotic cycle-endocycle transition.
Wumin Deng - One of the best experts on this subject based on the ideXlab platform.
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notch delta signaling induces a transition from mitotic cell cycle to endocycle in drosophila follicle cells
Development, 2001Co-Authors: Wumin Deng, Cassandra Althauser, Hannele RuoholabakerAbstract:In many developmental processes, polyploid cells are generated by a variation of the normal cell cycle called the endocycle in which cells increase their genomic content without dividing. How the transition from the normal mitotic cycle to endocycle is regulated is poorly understood. We show that the transition from mitotic cycle to endocycle in the Drosophila follicle cell epithelium is regulated by the Notch pathway. Loss of Notch function in follicle cells or its ligand Delta function in the underlying germline disrupts the normal transition of the follicle cells from mitotic cycle to endocycle, mitotic cycling continues, leading to overproliferation of these cells. The regulation is at the transcriptional level, as Su(H), a downstream transcription factor in the pathway, is also required cell autonomously in follicle cells for proper transitioning to the endocycle. One target of Notch and Su(H) is likely to be the G2/M cell cycle regulator String, a phosphatase that activates Cdc2 by dephosphorylation. String is normally repressed in the follicle cells just before the endocycle transition, but is expressed when Notch is inactivated. Analysis of the activity of String enhancer elements in follicle cells reveals the presence of an element that promotes Expression of String until just before the onset of polyploidy in wild-type follicle cells but well beyond this stage in Notch mutant follicle cells. This suggests that it may be the target of the endocycle promoting activity of the Notch pathway. A second element that is insensitive to Notch regulation promotes String Expression earlier in follicle cell development, which explains why Notch, while active at both stages, represses String only at the mitotic cycle-endocycle transition.
