“Highlights” 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.
Raging hormones (Peptide hormones as developmental growth and differentiation factors, by Esmond J. Sanders, Steve Harvey, Dev Dyn237:1537–1552) Feeling blue? Skin breaking out? Blame it on hormones. Organs growing? Cells differentiating? Could be the work of hormones, too. Peptide hormones are oft-neglected players among the many signals that shape the developing embryo. This is because they can work in an autocrine or paracrine manner, making it difficult to distinguish their primary function and their local cellular targets. In this review, Sanders and Harvey detail what's known about the developmental roles of several peptide hormones, including prolactin, growth hormone (GH), thyroid hormones, insulin, and others. Would it surprise you to learn that GH mediates not just growth, but also cell survival, blastocyst development, and neurogenesis? It's no wonder that peptide hormones are enraged—their important work has been underappreciated for far too long.
The eyes have it (The eye organizes neural crest cell migration, by Tobias Langenberg, Alon Kahana, Joseph A. Wszalek, Mary C. Halloran, Dev Dyn237:1645–1652) It has long been understood that many mesenchymal structures in and around the eye are derived from the pluripotent, migratory cell population, neural crest cells (NCCs). Yet the mechanisms that drive migration and differentiation of this NCC population remain unknown. Langenberg et al., approach this question in zebrafish, and first establish that the fate map and migration routes of NCCs from the diencephalon and mesencephalon to the eye and orbit are conserved with chick, and mouse. Next, they conduct a simple, yet telling, experiment. They ask, what happens to NCC migration and differentiation in the eyeless, chokh mutant? By analyzing gfp-labeled NCCs in live embryos, they observe that migration along a route that is dorsal anterior to the eye is slow and ill-directed. In line with this discovery, these mutants show a near complete loss of the ethmoid plate and orbital cartilage elements, structures derived from the dorsal anterior migrating NCC population. The results suggest that signals that direct specific aspects of NCC migration and POM differentiation emanate from the eye. The evidence leaves little room for naysayers.