Highlights in DD

“Highlights” is a new feature that calls attention to exciting advances in developmental biology that have recently been reported in Developmental Dynamics. Development is a broad field encompassing many important areas. To reflect this fact, the section will spotlight significant discoveries that occur across the entire spectrum of developmental events and problems: from new experimental approaches, to novel interpretations of results, to noteworthy findings utilizing different developmental organisms.

A frog's tale (Dev Dyn 235:2083–2094) Witnessing the remarkable metamorphosis from a tadpole to a frog has undoubtedly sparked a scientific curiosity in countless children. Still captivated by metamorphosis, Du Pasquier et al. dissect the process, which is largely regulated by apoptosis, at the molecular level. Their results from biochemistry, cell culture, and in vivo experiments suggest that Xenopus BID, a BCL2 death agonist, is truncated to its active form, tBID, by Caspase-8 during tail regression. Furthermore, they identify BID as a mediator in thyroid hormone–induced metamorphosis. These data reveal a physiological role for BID, which has been predominantly studied in cell culture.

In the beginning (Dev Dyn 235:2301–2314) How totipotent cells within the early embryo acquire separate identities provides a window into the very origins of life. Rossant and colleagues, leaders in the field of mammalian cell lineage specification, take a critical look at different models that depict establishment of the very first cell lineages: epiblast (future embryo), trophoectoderm (future placenta), and primitive endoderm (future yolk sac). Incorporating recent molecular data, the authors propose a new model for specification of the primitive endoderm. The review also covers other aspects of early patterning: lineage-restricted stem cells that can be derived from the three cell types, and polarity and axis formation in the blastocyst.

Beyond the microscope (Dev Dyn 235:2386–2400). Looking for a way to squeeze more data out of that precious specimen? Perhaps it is time to re-evaluate your imaging techniques. In this review, Dickinson deftly works through the strengths, weaknesses, and best applications for state-of-the-art imaging techniques such as ultrasound, MRI, and 3D analysis, as well as old standbys like fluorescence and confocal microscopy. Although she specifically addresses challenges associated with imaging mouse embryos, the techniques discussed can be used for many purposes.