Abstract: Series 101, Lecture 4
The Harvey Lectures Series 101 (2005—2006)
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Lecture #4: Thursday, February 16, 2006 — Time and Location
Making Heads and Tails of the Early Mouse Embryo
Elizabeth Robertson, PhD
Wellcome Trust Principal, Research Fellow
Wellcome Trust Centre for Human Genetics
University of Oxford
Oxford, UK
By the time the mouse embryo implants into the uterine epithelium 4 days after fertilization, it has developed three distinct tissue layers. The founder tissue of the embryo proper, the epiblast forms a radially symmetric cup of epithelial cells that grows in close apposition to the extra-embryonic ectoderm and the visceral endoderm. Reciprocal inductive interactions between these three cell populations orient the prospective anterior and posterior axis of embryo, trigger mesoderm induction, and initiate the process of gastrulation. Some years ago we discovered a novel growth factor, nodal, belonging to the TGF-ß superfamily that controls the very earliest cell fate decisions during axis patterning, essential for correct mesodermal cell growth and morphogenetic movements. Intriguingly nodal also determines the left-right axis, the process by which distinct and invariant handedness is conferred upon the embryonic body plan. We have exploited mouse genetics and ES cell methodologies to understand how dose dependent nodal signals, via its Smad family downstream effector molecules, govern specification of the primary body axes of the mammalian embryo.
Lecture Sponsor: Merck Research Laboratories
