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Patterning of the embryo: the first spatial decisions in the life of a mouse

Zernicka-Goetz, Magdalena (2002) Patterning of the embryo: the first spatial decisions in the life of a mouse. Development, 129 (4). pp. 815-829. ISSN 0950-1991.

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Although in most species the polarity of the embryo takes its roots from the spatial patterning of the egg, mammals were viewed as an exception. This was because the anteroposterior polarity of the mouse embryo could not be seen until gastrulation, and no developmental cues were known that could define polarity at earlier stages. Why should we now re-consider this view? While mechanisms of axis formation in mammals could, in principle, be unique, the evolutionary conservation of numerous other developmental processes raises the question of why mammals would have evolved a different way or timing of organising their embryonic polarity. Indeed, recent evidence shows that well before the onset of gastrulation, the mouse embryo initiates asymmetric patterns of gene expression in its visceral endoderm. Although this extra-embryonic tissue does not contribute to the body itself, it is involved in axis formation. Other recent work has revealed that spatial distribution of cells in the visceral endoderm can be traced back to polarity present at the blastocyst stage. These insights have raised the possibility that embryonic polarity might also originate early during development of mammalian embryos. Indeed it now appears that there are at least two spatial cues that operate in the mouse egg to shape polarity of the blastocyst. One of these is at the animal pole, which is defined by the site of female meiosis, and another is associated with the position of sperm entry. In this review I discuss these recent findings, which have led to the recognition that mouse embryos initiate development of their polarity at the earliest stages of their life. This novel perspective raises questions about the nature of cellular and molecular mechanisms that could convert developmental cues in the zygote to axes of the blastocyst, and hence into polarity of the post-implantation embryo. It also brings to light the need to understand how such mechanisms could enable early mouse development to be so regulative.

Item Type:Article
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URLURL TypeDescription
Zernicka-Goetz, Magdalena0000-0002-7004-2471
Additional Information:© 2002 The Company of Biologists. Accepted 16 November 2001. I apologise to all those authors whose original work I could not cite owing to limitation of space. I appreciate invaluable discussions with Chris Graham about patterning in early mouse development, and I also thank David Glover, Roger Pedersen and Peter Lawrence for kindly commenting on the draft of this manuscript. I am grateful to Lister Foundation for Preventive Medicine and Wellcome Trust for support, and I acknowledge my yet unborn daughter for keeping me company while I was writing this review.
Funding AgencyGrant Number
Lister Institute for Preventive MedicineUNSPECIFIED
Subject Keywords:Mouse, Embryo, Polarity, Axis, Cleavage, Fertilisation, Sperm
Issue or Number:4
Record Number:CaltechAUTHORS:20190422-100425160
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Official Citation:Patterning of the embryo: the first spatial decisions in the life of a mouse Magdalena Zernicka-Goetz Development 2002 129: 815-829
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:94841
Deposited By: George Porter
Deposited On:23 Apr 2019 15:34
Last Modified:03 Oct 2019 21:07

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