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Mechanisms of Primitive Streak Formation in the Mouse Embryo.
Author(s) -
Williams Margot L K,
Burdsal Carol,
Periasami Ammasi,
Sutherland Ann
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.483.1
Subject(s) - primitive streak , streak , embryo , microbiology and biotechnology , gastrulation , biology , chemistry , embryogenesis , mineralogy
During gastrulation, amniote embryos acquire the three primordial germ layers‐ endoderm, ectoderm, and mesoderm‐ via an epithelial to mesenchymal transition (EMT) that occurs at the primitive streak. Although the primitive streak is vital to the development of all mammals and birds, surprisingly little is known about how it forms and functions. While much has been learned from studies in the chick model system, it is unclear whether these results can be extrapolated to mammalian development. Results from live timelapse imaging and immuno‐fluorescent staining studies suggest that the streak does not form by rearrangement of a population of precursor cells (as in the chick), but rather by progressive induction of EMT in the posterior epiblast. This EMT is accompanied by progressive loss of basement membrane (BM) as the streak elongates, and is preceded by widespread weakening of the basement membrane in the embryo's posterior. This asymmetry represents a previously unknown aspect of early embryo patterning. Dynamic changes in cell‐ extracellular matrix associations in the region of the streak also predict differential roles for laminin and fibronectin in directing mesoderm migration. Our data indicate that the murine primitive streak does, in fact, form by mechanisms distinct from those in the chick. Supported by: NIH RO1 HD034807 , NIH T32 GM008136Grant Funding Source: NIH