The International journal of developmental biology最新文献

Michael Abercrombie is regarded as one of the principal pioneers of cell biology. Although Abercrombie began his career as an experimental embryologist, working on the avian organizer with C. H. Waddington, questions on how cells in culture migrate and interact dominated his career. Whilst studying the social behaviour of chick heart embryonic fibroblasts, Abercrombie identified a phenomenon whereby colliding cells collapse their protrusions towards the cell-cell contact upon a collision, preventing their continued migration. The cells then form protrusions away from the contact and, space permitting, migrate away from each other. This behaviour is now referred to as 'contact inhibition of locomotion' and has been identified within embryology as the driving force behind the directional migration of the neural crest and the dispersion patterning of haemocytes and Cajal-Retzius neurons. Furthermore, its loss between collisions of cancer cells and healthy cells is associated with metastasis. In this review we begin with an overview of Abercrombie's life and highlight some of his key publications. We then discuss Abercrombie's discovery of contact inhibition of locomotion, the roles which cell-cell adhesions, cell-matrix adhesions and the cytoskeleton play in facilitating this phenomenon, and the importance of contact inhibition of locomotion within the living organism.

The aim of this review is to highlight some of the key contributions to our understanding of craniofacial research from work carried out with the chicken and other avian embryos. From the very first observations of neural crest cell migration to the fusion of the primary palate, the chicken has proven indispensable in facilitating craniofacial research. In this review we will look back to the premolecular studies where "cut and paste" grafting experiments mapped the fate of cranial neural crest cells, the role of different tissue layers in patterning the face, and more recently the contribution of neural crest cells to jaw size and identity. In the late 80's the focus shifted to the molecular underpinnings of facial development and, in addition to grafting experiments, various chemicals and growth factors were being applied to the face. The chicken is above all else an experimental model, inviting hands-on manipulations. We describe the elegant discoveries made by directly controlling signaling either in the brain, in the pharyngeal arches or in the face itself. We cover how sonic hedgehog (Shh) signals to the face and how various growth factors regulate facial prominence identity, growth and fusion. We also review abnormal craniofacial development and how several type of spontaneous chicken mutants shed new light on diseases affecting the primary cilium in humans. Finally, we bring out the very important role that the bird beak has played in understanding amniote evolution. The chicken, duck and quail have been and will continue to be used as experimental models to explore the evolution of jaw diversity and the morphological constraints of the vertebrate face.

Signalling pathways that regulate neural progenitor proliferation and neuronal differentiation have been identified. However, we know much less about how transduction of such signals is regulated within neuroepithelial cells to direct cell fate choice during mitosis and subsequent neuronal differentiation. Here we review recent advances in the experimentally amenable chick embryo, which reveal that this involves association of signalling pathway components with cell biological entities, including mitotic centrosomes and ciliary structures. This includes changing centrosomal localization of protein kinase A, which regulates Sonic hedgehog signalling and so neural progenitor status, and Mindbomb1, a mediator of Notch ligand activation, which promotes Notch signalling in neighbouring cells, and so is active in presumptive neurons. We further review cell biological events that underlie the later step of neuronal delamination, during which a newborn neuron detaches from its neighbouring cells and undergoes a process known as apical abscission. This involves inter-dependent actin and microtubule dynamics and includes dissociation of the centrosome from the ciliary membrane, which potentially alters the signalling repertoire of this now post-mitotic cell. Open questions and future directions are discussed along with technological advances which improve accuracy of gene manipulation, monitoring of protein dynamics and quantification of cell biological processes in living tissues.

When I was asked by the Chief Editor of the Int. J. Dev. Biol. to consider editing a Special Issue about "the chick", I was first hesitant, because I had already edited such an issue for another journal in 2004 (Mech. Dev. volume 121), when the sequence of the chick genome was first released (Stern, 2004, 2005). But at the same time I was surprised that this journal, well known for its Special Issues of which many have become important historical and literary land-marks to the developmental biology literature, had not yet produced a volume on what is probably the oldest developmental model system. Despite this, it is often forgotten that much of what we know (or think we know) about human developmental events is due to extrapolation from chick embryological studies.

The chick embryo has served as a workhorse for experimental embryological studies designed to elucidate mechanisms underlying neurulation, the process that forms the neural tube, the rudiment of the entire adult central nervous system. Early chick embryos developing in whole-embryo culture can be readily manipulated in cut-and-paste-type experiments, and this attribute makes this model system unparalleled for studying the morphogenesis of embryos and their organ rudiments. How the chick embryo and experimental embryology have contributed to our understanding of critical events of neurulation are summarized.

The formation and wiring of the vertebrate nervous system involves the spatially and temporally ordered production of diverse neuronal and glial subtypes that are molecularly and functionally distinct. The chick embryo has been the experimental model of choice for many of the studies that have led to our current understanding of this process, and has presaged and informed a wide range of complementary genetic studies, in particular in the mouse. The versatility and tractability of chick embryos means that it remains an important model system for many investigators in the field. Here we will focus on the role of Sonic hedgehog (Shh) signaling in coordinating the diversification, patterning, growth and differentiation of the vertebrate nervous system. We highlight how studies in chick led to the identification of the role Shh plays in the developing neural tube and how subsequent work, including studies in the chick and the mouse revealed details of the cell intrinsic programs controlling cell fate determination. We compare these mechanisms at different rostral-caudal positions along the neuraxis and discuss the particular experimental attributes of the chick that facilitated this work.

Absolute time elapsed since fertilization, or hours' incubation, is not a good measure of the precise degree of development of an embryo because there is considerable variation. The chick embryo benefits from a detailed, well defined staging system introduced by Hamburger and Hamilton in 1951, perhaps the most precise and detailed available for any species. This paper briefly reviews the background and legacy of this table, including the remarkable work of its predecessors, Mathias Duval and Franz Keibel. It also begs the question of why the mouse embryo still lacks a similarly precise classification.

Primordial germ cells (PGCs) are the founder cells for mature gametes, the vehicles by which individuals transmit genetic and epigenetic information to later generations. Since the 19^th century, avian species (chickens in particular) have been widely used for germ cell research. Previous studies have used chicken PGCs for a variety of research applications, including as a model for studies focusing on germline development. Other applications of chicken PGCs, including conservation efforts for avian species and methods of producing transgenic birds, have further reinforced the importance of these cells. However, much remains to be revealed about the origin and role of PGCs during their development in the chicken. Here, we provide a comprehensive review of chicken PGCs, focusing in particular upon their initial profiles and physiological changes during development as regulated by environmental factors and/or intrinsic mechanisms. We also emphasise sex-dependent differences in PGC development after settlement within the gonads, as well as future applications for avian PGCs.

This paper provides a brief account of some aspects of the career of Ruth Bellairs using selected examples from her research publications, with the emphasis being placed on the early stages of chick embryo development, and in particular, on cell migration. Topics include the role of Hensen's node, the vitelline membrane, the structure and segmentation of somites, the tail bud and the Wolffian duct. Her research approach has involved embryo culture, experimental surgery, transmission and scanning electron microscopy, time-lapse filming and immunostaining techniques.

My career in research was a second thought. I first (during 8 years) worked as a secondary school teacher and after 4-5 years, during which my two daughters were born, I found a way to escape from what was to be a lifetime job. For two years, my initiation to research was limited to the free time left by my teaching duties. This period of time was a bit "complicated" but not enough to prevent me to realize that research was really what I wanted to do for the rest of my life… And this was when I became acquainted with the chick embryo. This companionship later became extended to another representative of the avian world: the quail (Coturnix coturnix japonica). I recall in the following lines a survey of scientific stories that came out from my association with these precious animals, ... not without a feeling of gratitude.