PURPOSE To determine the localization of retinoic acid receptors (RAR) alpha, beta, and gamma and retinoid X receptors (RXR) alpha, beta, and gamma in developing and adult mouse eyes at the level of single cells. METHODS Immunohistochemistry was performed on paraformaldehyde-lysine-periodate-fixed cryosections of mouse eyes, from embryonic day 10.5 to adulthood, with polyclonal antibodies dir...

Most vertebrate organs are composed of epithelium surrounded by support and stromal tissues formed from mesenchyme cells, which are not generally thought to form organized progenitor pools. Here, we use clonal cell labeling with multicolor reporters to characterize individual mesenchymal progenitors in the developing mouse lung. We observe a diversity of mesenchymal progenitor populations with ...

Between February 1969 and August 1970 Edward Kollar and Grace Baird, at the University of Chicago [8] in Chicago, Illinois, published three papers that described a series of experiments using teeth from mouse [9] embryos. Drawing upon a history of using tissue interactions to understand differentiation [10], Kollar and Baird designed their experiments to reveal how differentiated structures bec...

The existence of common mechanisms regulating organ regeneration is an intriguing concept. Here we report on a regulatory element that is transiently activated during heart and fin regeneration in zebrafish. This element contains a ctgfa upstream sequence, called careg, which is induced by TGFβ/Activin-β signalling in the peri-injury zone of the myocardium and the fin mesenchyme. In addition, t...

Inductive signals cause conversion of mesenchyme into epithelia during the formation of many organs. Yet a century of study has not revealed the inducing molecules. Using a standard model of induction, we found that ureteric bud cells secrete factors that convert kidney mesenchyme to epithelia that, remarkably, then form nephrons. Purification and sequencing of one such factor identified it as ...

It is generally proposed that embryonic mesenchymal cells use sulfated macromolecules during in situ migration. Attempts to resolve the molecular mechanisms for this hypothesis using planar substrates have been met with limited success. In the present study, we provide evidence that the functional significance of certain sulfated macromolecules during mesenchyme migration required the presence ...

RATIONALE The cardiac venous pole is a common focus of congenital malformations and atrial arrhythmias, yet little is known about the cellular and molecular mechanisms that regulate its development. The systemic venous return myocardium (sinus node and sinus horns) forms only late in cardiogenesis from a pool of pericardial mesenchymal precursor cells. OBJECTIVE To analyze the cellular and mo...

Previous studies indicate that the transformation of cardiac endothelium into mesenchyme is dependent upon a developmentally regulated signal expressed by its associated myocardium. This process can be mimicked in culture by substituting a non-cytolytic EDTA extract of embryonic heart tissue for the presence of myocardium. Polyclonal antibodies (ES1) generated against the EDTA-extractable prote...

The mammary glands develop initially as buds arising from the ventral embryonic epidermis. Recent work has shed light on signaling pathways leading to the patterning and formation of the mammary placodes and buds in mouse embryos. Relatively little is known of the signaling pathways that initiate branching morphogenesis and the formation of the ducts from the embryonic buds. Previous studies ha...

Ethanol is a well-recognized teratogen in vertebrates that can perturb the development of the facial primordia and various other embryonic structures. However,the mechanisms underlying alcohol's effects on embryogenesis are currently unclear. Recent evidence suggests that the cranial neural crest, which forms the entire facial skeleton, may be a particularly sensitive target of ethanol teratoge...