The Development of Normal and Homozygous Brachy (T/T) Mouse Embryos in the Extraembryonic Coelom of the Chick

Abstract

The graphical method here described for estimating inner products can be applied in a variety of computational problems. 1 The author wishes to express his indebtedness to the Carnegie Corporation of New York for a research grant in support of our development of multiple factor analysis and its application to the study of primary mental abilities.

The murine allantois: emerging paradigms in development of the mammalian umbilical cord and its relation to the fetus

“…That the allantois shares spatial coordinates with the embryonic A-P axis is supported by a number of observations. T/T and T C /T C embryos display axial defects, including a truncated posterior region and foreshortened allantois (Chesley, 1935;Zavadskaia and Kobozieff, 1930;Gluecksohn-Schoenheimer, 1944;Searde, 1966). Disruptions of T expression are associated with a number of other mouse mutants exhibiting defective A-P patterning among which are Tcf3, LPP3, and axin, which show near complete or complete axis duplications (EscalanteAlcalde et al, 2003;Gluecksohn-Schoenheimer, 1949;Merrill et al, 2004;Perry et al, 1995;Zeng et al, 1997).…”

“…For example, it has generally been accepted that embryo morbidity in homozygous T and its alleles (Herrmann, 1991;Searle, 1966) is due to failure of the allantois to fuse with the chorion (Gluecksohn-Schoenheimer, 1944). Recent studies of cell proliferation and death reveal, however, that T C /T C mutant allantoises fail to elongate, but T C /T C allantoises surpassing 220 lm in length exhibit distal VCAM-1 (Inman and Downs, 2006b).…”

T‐box genes in early embryogenesis

“…In T -/-embryos, the primitive streak is condensed and thick relative to wild-type littermates (Chesley, 1935;Gluecksohn-Schoenheimer, 1938, 1944Gruneberg, 1958). By embryonic day eight (E8), the mesoderm: ectoderm ratio is elevated 15% in the posterior portions of mutant embryos while remaining normal in the anterior half (Yanagisawa et al, 1981).…”

“…Defects in mesoderm migration also affect extra-embryonic mesoderm, eventually affecting the formation of the allantois, which subsequently fails to contact the chorion. Thus, the mutant embryos lack a proper placental connection and this ultimately accounts for their death at approximately E10.5 (Gluecksohn-Schoenheimer, 1938, 1944Wilson et al, 1993).…”

Molecular basis for skeletal variation: insights from developmental genetic studies in mice

“…Consistent with this expression pattern, malformations in embryos homozygous for mutant T alleles include a blockade of elongation of the axis, in which the anterior portion of the notochord initially forms but does not persist as a coherent structure (Gluecksohn-Schoenheimer, 1944;Herrmann, 1991;Wilkinson et al, 1990). Furthermore, mutants do not develop structures posterior to the forelimb buds.…”