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Dorsal and ventral aspects of the eye are distinct from the early stages of development. The developing eye cup grows dorsally, and the choroidal fissure is formed on its ventral side. Retinal axons from the dorsal and ventral retina project to the ventral and dorsal tectum, respectively. Misexpression of the Tbx5 gene induced dorsalization of the ventral(More)
Despite extensive studies on the anterior-posterior (AP) axis formation of limb buds, mechanisms that specify digit identities along the AP axis remain obscure. Using the four-digit chick leg as a model, we report here that Tbx2 and Tbx3 specify the digit identities of digits IV and III, respectively. Misexpression of Tbx2 and Tbx3 induced posterior(More)
Human mutations in TBX5, a gene encoding a T-box transcription factor, and SALL4, a gene encoding a zinc-finger transcription factor, cause similar upper limb and heart defects. Here we show that Tbx5 regulates Sall4 expression in the developing mouse forelimb and heart; mice heterozygous for a gene trap allele of Sall4 show limb and heart defects that(More)
Much progress has been made in understanding limb development. Most genes are expressed equally and in the same pattern in the fore- and hindlimbs, which nevertheless develop into distinct structures. The T-box genes Tbx5 and Tbx4, on the other hand, are expressed differently in chick wing (Tbx5) and leg (Tbx4) buds. Molecular analysis of the optomotor(More)
The emergence of terrestrial life witnessed the need for more sophisticated circulatory systems. This has evolved in birds, mammals and crocodilians into complete septation of the heart into left and right sides, allowing separate pulmonary and systemic circulatory systems, a key requirement for the evolution of endothermy. However, the evolution of the(More)
To elucidate the function of the T-box transcription factor Tbx20 in mammalian development, we generated a graded loss-of-function series by transgenic RNA interference in entirely embryonic stem cell-derived mouse embryos. Complete Tbx20 knockdown resulted in defects in heart formation, including hypoplasia of the outflow tract and right ventricle, which(More)
HtrA1, a member of the mammalian HtrA serine protease family, has a highly conserved protease domain followed by a PDZ domain. Because HtrA1 is a secretory protein and has another functional domain with homology to follistatin, we examined whether HtrA1 functions as an antagonist of Tgfbeta family proteins. During embryo development, mouse HtrA1 was(More)
Mammalian heart development requires precise allocation of cardiac progenitors. The existence of a multipotent progenitor for all anatomic and cellular components of the heart has been predicted but its identity and contribution to the two cardiac progenitor 'fields' has remained undefined. Here we show, using clonal genetic fate mapping, that Mesp1+ cells(More)
The role of Lefty2 in left-right patterning was investigated by analysis of mutant mice that lack asymmetric expression of lefty2. These animals exhibited various situs defects including left isomerism. The asymmetric expression of nodal was prolonged and the expression of Pitx2 was upregulated in the mutant embryos. The absence of Lefty2 conferred on Nodal(More)
Extensive misexpression studies were carried out to explore the roles played by Tbx5, the expression of which is excluded from the right ventricle (RV) during cardiogenesis. When Tbx5 was misexpressed ubiquitously, ventricular septum was not formed, resulting in a single ventricle. In such heart, left ventricle (LV)-specific ANF gene was induced. In search(More)