Highlights in DD

Abstract

"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. (Dev Dyn 236:2493-2501 A mouse could never be mistaken for a chicken-unless their neural crests are being compared. Neural crest cells migrate from the neural tube to various tissues, where they differentiate into several cell types. Chick neural crest migration is under the control of bone morphogenetic proteins (BMPs). Seemingly in agreement, Bmp2 null mice lack migratory crest. But, is the mouse phenotype due to defects in migration or induction of crest fate? Correia et al. put this question to rest. Consistent with a role in migration, they show that early crest markers are induced in Bmp2 null embryos, but the cells remain associated with the neural tube. However, when they dig deeper, they find direct comparisons between mouse and chick neural crest falter. Whereas chick Cad6B is only expressed in premigratory crest, it is also in migratory crest in mouse. Additionally, unlike in chick, mouse neural crest Cad6B, Id2, and Wnt1 expression is not regulated by BMPs. The data illustrate that, although the top of the neural crest migration hierarchy is the same, downstream mechanisms differ. Similar yet differentNot-so-"bad" cholesterol (Dev Dyn 236:2708 -2712) Ever get a craving for fried food? You are not the only one. Work by Zhao and colleagues suggests that, at times, oligodendrocytes cannot get enough "bad" cholesterol either. Differentiated oligodendrocytes form a cholesterol-rich myelin sheath that enhances conduction of electrical signals along axons. One way that central nervous system glia procure cholesterol is by synthesizing their own. Here, the authors find evidence that the cells also uptake cholesterol from the surrounding environment. Mature oligodendrocytes express very low-density lipoprotein receptors (VLDLRs) and LDLRs in the spinal cord and brain, with some regional differences between the two. Highest expression of both receptors coincides with the peak of myelination in mouse spinal cords. These findings suggest that oligodendrocytes endocytose LDL and VLDL, and use them to build the myelin sheath. Apparently oligodendrocytes cannot get too much of a bad, er good, thing. (Dev Dyn 236:2792-2799 In the face of an unpredictable food supply, the body's ability to adjust energy usage and storage is integral to survival. Energy homeostasis is a product of crosstalk between specific neurons in the hypothalamus and brainstem, and cues from the periphery, such as adipose tissue. Simon et al. show that, in the absence of the homeobox gene Sax2, these signals get crossed. Despite sufficient intake ...