“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 star is born (Dev Dyn236:335–352) Botryllus schlosseri, commonly called the star ascidian, earns its name from the pretty, stellate colony formed by a group of asexually reproducing animals, or zooids. The organism has proven a useful model for morphogenesis, regeneration, allorecognition, and apoptosis. One confounding problem facing B. schlosseri biologists is lack of a common staging system. Here, Manni et al. present staging of the colonial life cycle in relation to important developmental events. Staging is supported by histology, diagrams, detailed descriptions of morphogenesis, and comparisons to other staging methods. The authors also explain the particular usefulness of B. schlosseri in studying a variety of biological phenomenon. Just as Kimmel et al. and Hamburger and Hamilton are indispensable for zebrafish and chicken staging, surely B. schlosseri biologists will come to depend on Manni et al.

When good cells go bad (Dev Dyn236:364–373) Tightly packed side-by-side, polarized epithelial cells form protective barriers lining the body's cavities, lumens, and surfaces. In their study, Szafranski and Goode use the Drosophila oocyte as a model to investigate why, in certain circumstances, the protectors lose their integrity and become invaders. They report that loss of components in basolateral junctions (BLJ), but not other epithelial junctions, induces follicular epithelial cells to invade neighboring germ cells. Events before induced invasion mirror natural events as both BLJ mutants and wild-type follicular border cells (BCs) undergo “membrane lateralization,” a loss of some junctional proteins and redistribution of others. Membrane lateralization is necessary, but not sufficient for invasion. The authors also show that overexpression of dominant-negative Rac1, a G-protein required for BC motility, suppresses migration of BLJ mutant cells. Together their data suggest that BLJ proteins work together as a supermolecular complex to prevent epithelial cell invasion by suppressing membrane lateralization and Rac motility pathways. Parallels to tumor invasion in human carcinomas are discussed.

Profiling Fetal Alcohol Syndrome (Dev Dyn236:613–631) Fetal alcohol syndrome (FAS), a tragic consequence of a mother's overindulgence, can cause craniofacial defects, mental retardation, and stunted growth. In their study, Knudsen and colleagues provide evidence that changes in gene expression within specific molecular pathways are the bases for induced phenotypes. Microarray analysis of mouse cranial neural folds shows that pathways involved in cytoskeletal reorganization, namely tight junction, adherens junction, and focal adhesion pathways, are significantly up-regulated in response to alcohol. Of interest, defects are less severe in the C57BL/6 substrain B6N than in B6J. Furthermore, PK11195, a ligand for the mitochondrial 18-kDa translocator protein (TSPO), counteracts alcohol affects in B6J, but exacerbates them in B6N. The different responses may be attributed to genetic variation. Indeed, additional alcohol-induced changes are found in B6N alone, namely downregulation of ribosomal and proteosome, and up-regulation of glycolysis and pentose phosphate pathways. These data suggest that TSPO plays a role in susceptibility to FAS.