Editorial: Signaling Pathways in Embryonic Development (original) (raw)

1998 warkany lecture: Signaling pathways in development

Teratology, 1999

Cell-cell signaling pervades all aspects of development, not just in vertebrates, but in all animals (metazoa). It is a typifying characteristic of the major multicellular life forms, animals, plants, and fungi, which diverged about 1.2 billion years ago from a common ancestor descended from a lineage of unicellular life forms. In metazoa, at least 17 kinds of signal transduction pathways operate, each distinguished by its transduction intermediates. Five kinds predominate in early embryonic development, namely, the Wnt, TGF-␤, Hedgehog, RTK, and Notch pathways. Five more are used in late development, and seven more in the functions of differentiated cells. The pathways must have evolved and become conserved in pre-Cambrian times before the divergence of basal members of most of the modern phyla. In metazoan development and physiology, the responses of cells to intercellular signals include cell proliferation, secretion, motility, and transcription. These responses tend to be conserved among metazoa and shared with unicellular eukaryotes and in some cases even with unicellular prokaryotes. Protein components of the responses date back 2 billion years to ancestral eukaryotes or 3 billion to ancestral prokaryotes. Each metazoan developmental process consists of a network of signals and responses, and many of these networks are conserved among metazoa, for example, by insects and mammals. The study of model organisms, even of nonvertebrate groups, is expected to continue to contribute greatly to the understanding of mammalian development and to offer opportunities to analyze the effects of toxicants on development, as well as opportunities to devise incisive assays for toxicants.

Summary of Second Workshop on Structural Birth Defects

Developmental Biology, 1999

Birth defects are the leading cause of infant mortality in the United States and contribute significantly to developmental disabilities of infancy, childhood, adolescence, and adult life. In addition to the emotional stress on families and afflicted individuals, the economic impact is enormous with estimates of lifetime costs in the range of tens of billions of dollars for those affected annually in the United States. Moreover, unlike other major causes of infant mortality that have been dramatically reduced in recent decades, such as sudden infant death and respiratory distress syndromes, the frequency of birth defects has not changed appreciably. Three to four percent of live-born babies have a major congenital defect. Approximately 15-20% of pregnancies end in a spontaneous abortion, most of which are associated with a developmental defect or chromosomal abnormality. Recently, however, advances in developmental and molecular biology, genetics, and other biotechnologies and disciplines have provided medical science with an armamentarium of new tools to dissect and understand the complex biological and genetic mechanisms responsible for birth defects. A primary goal of the National Institute of Child Health and Human Development (NICHD) is to encourage research on the molecular susceptibility to and etiology of human birth defects. On July 20-21, 1998, the Developmental Biology, Genetics and Teratology Branch of the Center for Research for Mothers and Children, NICHD, convened the second in a series of workshops on structural birth defects. While the first workshop focused on clinical and epidemiological aspects of structural birth defects, this second workshop highlighted basic developmental and molecular biology, molecular genetics, and other fundamental disciplines. The purpose of the workshop was to develop recommendations for multidisciplinary approaches to advance our understanding of normal and abnormal development. Supporting basic research in this area will improve our knowledge and understanding of the underlying mechanisms associated with the formation of structural birth defects and will ultimately result in our ability to prevent them. The workshop was chaired by Dr. Merton Bernfield, Children's Hospital, Harvard Medical School. Participants included distinguished developmental biologists from the scientific community as well as representatives from the Centers for Disease Control and Prevention, the Environmental Protection Agency, and other institutes within the National Institutes of Health. The participants agreed with the mandated objective to develop and prioritize research recommendations in order to advance our understanding of

Genetic and evolutional mechanisms explain associated malformations–a 'G–E–M'concept

Medical hypotheses, 2007

During the process of evolution, segmented structures like heart and kidneys appeared earlier than vertebral column. Single piece notochord was transformed into segmented vertebral column. Ribs followed the segmented vertebral column but preceded the fore limbs in evolution. Segmentation is the underlying principle of the body plan even in annelids and arthropods. In these animals apart from vertebral column; segmentation is obvious in other structures like kidneys and heart. Somewhere on the temporal axis of evolution--vertebral column, heart and kidneys have evolved together; and have shared the genetic control of embryological morphogenesis. Mutations or micro-evolution in homeotic--Hox--genes led to macro evolution and a sudden change in morphology, when six-legged insects diverged from crustacean-like arthropod ancestors with multiple limbs. The control of embryonic morphology has been highly conserved in evolution between vertebrates and invertebrates and Hox genes occupy a central role in the scheme of molecular control of early morphogenesis. Mutations affecting regulatory genes, including those containing homeobox sequences, have been important. Malformations and association like VACTERL can be rationally explained considering the genetic and evolutional mechanisms controlling morphogenesis.

Signalling Pathways in Embryonic Development

2017

Frontiers is more than just an open-access publisher of scholarly articles: it is a pioneering approach to the world of academia, radically improving the way scholarly research is managed. The grand vision of Frontiers is a world where all people have an equal opportunity to seek, share and generate knowledge. Frontiers provides immediate and permanent online open access to all its publications, but this alone is not enough to realize our grand goals. Frontiers Journal Series The Frontiers Journal Series is a multi-tier and interdisciplinary set of open-access, online journals, promising a paradigm shift from the current review, selection and dissemination processes in academic publishing. All Frontiers journals are driven by researchers for researchers; therefore, they constitute a service to the scholarly community. At the same time, the Frontiers Journal Series operates on a revolutionary invention, the tiered publishing system, initially addressing specific communities of scholars, and gradually climbing up to broader public understanding, thus serving the interests of the lay society, too. Dedication to Quality Each Frontiers article is a landmark of the highest quality, thanks to genuinely collaborative interactions between authors and review editors, who include some of the world's best academicians. Research must be certified by peers before entering a stream of knowledge that may eventually reach the public-and shape society; therefore, Frontiers only applies the most rigorous and unbiased reviews. Frontiers revolutionizes research publishing by freely delivering the most outstanding research, evaluated with no bias from both the academic and social point of view. By applying the most advanced information technologies, Frontiers is catapulting scholarly publishing into a new generation. What are Frontiers Research Topics? Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial