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Early patterning of the mouse embryo -- contributions of sperm and egg

Piotrowska, Karolina and Zernicka-Goetz, Magdalena (2002) Early patterning of the mouse embryo -- contributions of sperm and egg. Development, 129 (24). pp. 5803-5813. ISSN 0950-1991. doi:10.1242/dev.00170.

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The first cleavage of the fertilised mouse egg divides the zygote into two cells that have a tendency to follow distinguishable fates. One divides first and contributes its progeny predominantly to the embryonic part of the blastocyst, while the other, later dividing cell, contributes mainly to the abembryonic part. We have previously observed that both the plane of this first cleavage and the subsequent order of blastomere division tend to correlate with the position of the fertilisation cone that forms after sperm entry. But does sperm entry contribute to assigning the distinguishable fates to the first two blastomeres or is their fate an intrinsic property of the egg itself? To answer this question we examined the distribution of the progeny of early blastomeres in embryos never penetrated by sperm — parthenogenetic embryos. In contrast to fertilised eggs, we found there is no tendency for the first two parthenogenetic blastomeres to follow different fates. This outcome is independent of whether parthenogenetic eggs are haploid or diploid. Also unlike fertilised eggs, the first 2-cell blastomere to divide in parthenogenetic embryo does not necessarily contribute more cells to the blastocyst. However, even when descendants of the first dividing blastomere do predominate, they show no strong predisposition to occupy the embryonic part. Thus blastomere fate does not appear to be decided by differential cell division alone. Finally, when the cortical cytoplasm at the site of sperm entry is removed, the first cleavage plane no longer tends to divide the embryo into embryonic and abembryonic parts. Together these results indicate that in normal development fertilisation contributes to setting up embryonic patterning, alongside the role of the egg.

Item Type:Article
Related URLs:
URLURL TypeDescription Information
Zernicka-Goetz, Magdalena0000-0002-7004-2471
Additional Information:© 2002 The Company of Biologists. Accepted 12 September 2002. We thank David Glover, Stephen Frankenberg, Jonathon Pines, Roger Pedersen and Chris Graham for their comments on the draft of this manuscript. M. Z. G. is grateful to the Wellcome Trust for their support. K. P. thanks Marie Currie for the Fellowship.
Funding AgencyGrant Number
Marie Curie FellowshipUNSPECIFIED
Subject Keywords:Sperm, Egg, Polarity, Cleavage, Blastocyst pattern, mouse
Issue or Number:24
Record Number:CaltechAUTHORS:20190422-100408698
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Official Citation:Early patterning of the mouse embryo — contributions of sperm and egg Karolina Piotrowska, Magdalena Zernicka-Goetz Development 2002 129: 5803-5813; doi: 10.1242/dev.00170
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:94837
Deposited By: George Porter
Deposited On:23 Apr 2019 15:57
Last Modified:16 Nov 2021 17:08

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