Growing an Embryo from a Single Cell: A Hurdle in Animal Life
TLDR
In mammals and in endoparasites, development in a nutritive environment releases the growth constraint, but growth of cells before gastrulation requires a new program to sustain pluripotency during this growth.Abstract:
A requirement that an animal be able to feed to grow constrains how a cell can grow into an animal, and it forces an alternation between growth (increase in mass) and proliferation (increase in cell number). A growth-only phase that transforms a stem cell of ordinary proportions into a huge cell, the oocyte, requires dramatic adaptations to help a nucleus direct a 10(5)-fold expansion of cytoplasmic volume. Proliferation without growth transforms the huge egg into an embryo while still accommodating an impotent nucleus overwhelmed by the voluminous cytoplasm. This growth program characterizes animals that deposit their eggs externally, but it is changed in mammals and in endoparasites. In these organisms, development in a nutritive environment releases the growth constraint, but growth of cells before gastrulation requires a new program to sustain pluripotency during this growth.read more
Citations
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Nothing in Biology Makes Sense Except in the Light of Evolution
TL;DR: The theory that biological species are descended from common ancestors provides an indispensable heuristic to understand why living organisms are what they are and do what they do.
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Expression of engrailed proteins in arthropods, annelids and chordates
TL;DR: A monoclonal antibody is described that recognizes a conserved epitope in the homeodomain of engrailed proteins of a number of different arthropods, annelids, and chordates; this antibody is used to isolate the grasshopperEngrailed gene, a homeobox gene that has an important role in Drosophila segmentation.
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Zygotic Genome Activation in Vertebrates.
TL;DR: Progress in understanding vertebrate ZGA dynamics in frogs, fish, mice, and humans is reviewed to explore differences and emphasize common features.
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Waves of Cdk1 Activity in S Phase Synchronize the Cell Cycle in Drosophila Embryos
TL;DR: In Drosophila embryos, Cdk1 positive feedback serves primarily to ensure the rapid onset of mitosis, while wave propagation is regulated by S phase events, demonstrating a fundamental distinction between S phase Cdk 1 waves, which propagate as active trigger waves in an excitable medium, and mitotic Cdk2 waves, who propagate as passive phase waves.
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Capturing Totipotent Stem Cells
TL;DR: The biological and molecular characterization of cultured cells with developmental potential similar to totipotent blastomeres are reviewed, and recent progress toward the capture and stabilization of the totip powerless state in vitro is assessed.
References
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Journal ArticleDOI
Stable intronic sequence RNA (sisRNA), a new class of noncoding RNA from the oocyte nucleus of Xenopus tropicalis
TL;DR: Stable intronic sequence RNA (sisRNA) from the oocyte nucleus constitutes a new class of noncoding RNA and its transmission to the developing embryo suggest that it may play important regulatory roles during oogenesis and/or early embryogenesis.
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Arthropod-like Expression Patterns of engrailed and wingless in the Annelid Platynereis dumerilii Suggest a Role in Segment Formation
Benjamin Prud'homme,Renaud de Rosa,Detlev Arendt,Jean-François Julien,Rafael Pajaziti,Adriaan Dorresteijn,André Adoutte,Joachim Wittbrodt,Guillaume Balavoine +8 more
TL;DR: The expression patterns of genes orthologous to the arthropod segmentation genes engrailed and wingless in the annelid Platynereis dumerilii are reported as molecular evidence of a segmented ancestor of protostomes.
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Fluctuations in cyclin e levels are required for multiple rounds of endocycle s phase in drosophila
TL;DR: The results indicate that endocycle S phases require oscillations in Cdk activity, but, in contrast to oscillation in mitotic cells, these occur independently of mitosis.
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Cell Cycle and Developmental Regulations of Replication Factors in Mouse Embryonic Stem Cells
TL;DR: The transcript levels of almost all the cell cycle regulators investigated except for p21 and p27 are higher in undifferentiated ES cells than in murine embryonic fibroblasts (MEFs), and the increased stability of mRNA in ES cells may be partially responsible for this at least with some of the factors.
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On the coupling between DNA replication and mitosis
John Newport,Mary Dasso +1 more
TL;DR: Investigation of the transition from the rapid, early cell cycle to the slower, more somatic-like cell cycle that occurs after division twelve in developing Xenopus embryos, a stage called the mid-blastula transition (MBT), has shown that at high concentrations of nuclei the in vitro cycle is extended.
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