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
More filters
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.
Journal ArticleDOI
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.
Journal ArticleDOI
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.
Journal ArticleDOI
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.
Journal ArticleDOI
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
More filters
Journal ArticleDOI
Differential synthesis of the genes for ribosomal RNA during amphibian oögenesis.
TL;DR: The ovarian DNA of Xenopus is described and it is demonstrated that it contains an excess of sequences coding for rRNA, which is particularly striking in ovaries of the toads Bufo and Xenopus, in which the differential synthesis occurs during pachytene.
Journal ArticleDOI
The histone H3.3 chaperone HIRA is essential for chromatin assembly in the male pronucleus
Benjamin Loppin,Emilie Bonnefoy,Caroline Anselme,Anne Laurençon,Timothy L. Karr,Pierre Couble +5 more
TL;DR: It is shown that ssm is a point mutation in the Hira gene, thus demonstrating that the histone chaperone protein HIRA is required for nucleosome assembly during sperm nucleus decondensation, and that nucleosomes containing H3.3, and not H3, are specifically assembled in paternal Drosophila chromatin before the first round of DNA replication.
Journal ArticleDOI
Cell cycle control by the nucleo-cytoplasmic ratio in early Drosophila development
TL;DR: Transcription patterns in haploid embryos indicate that transcriptional activation is not directly controlled by the nucleo-cytoplasmic ratio, but may be an effect of the lengthening of interphase periods.
Journal ArticleDOI
Distinct molecular mechanisms regulate cell cycle timing at successive stages of Drosophila embryogenesis
TL;DR: During cell cycles 2-7, Cdc2/Cyclin complexes are continuously present and show little fluctuation in abundance, phosphomodification, or activity, which suggests that cycling of the mitotic apparatus does not require cytoplasmic oscillations of known regulatory activities.
Related Papers (5)
A major developmental transition in early xenopus embryos: I. characterization and timing of cellular changes at the midblastula stage
Studies of nuclear and cytoplasmic behaviour during the five mitotic cycles that precede gastrulation in Drosophila embryogenesis
V.E. Foe,B.M. Alberts +1 more