Gene Activity In Early Development

The new third edition of Gene Activity in Early Development reflects the ten years of technological progress since the last edition. Providing a unique blend of classical and molecular knowledge, it discusses all major embryonic systems from both a comparative and mechanistic point of view. In deriving overall interpretations of developmental phenomena, it brings into play all the disparate forms of evidence, including genetic, molecular, and cytological.**This book is written for any serious student or scholar entering the field, whether his or her background is in genetics, molecular biology, or embryology.

Gene Activity in Early Development, Second Edition is devoted to gene activity in early development, considering the estimates of RNA and protein synthesis rates, complexities, and amounts. A quantitative treatment of some of the key classes of macromolecules in early embryos and oocytes is also offered. This edition is organized into eight chapters and begins with an overview of the variable gene activity theory of cell differentiation, emphasizing the transcription level regulation as the fundamental process underlying differentiation and development. The following chapters explore the genome regulation of embryogenesis, differential embryo cell function, and transcription and protein synthesis in early embryos. The reader is also introduced to direct measurements regarding the DNA sequences transcribed during early development and localization of morphogenetic determinants in egg cytoplasm. The book concludes with a discussion of the structure of lampbrush chromosomes and the synthesis of heterogeneous nuclear and messenger RNAs during oogenesis. This book will prove useful to students as well as established researchers interested in developmental genetics.

Eggs of all animals contain mRNAs and proteins that are supplied to or deposited in the egg as it develops during oogenesis. These maternal gene products regulate all aspects of oocyte development, and an embryo fully relies on these maternal gene products for all aspects of its early development, including fertilization, transitions between meiotic and mitotic cell cycles, and activation of its own genome. Given the diverse processes required to produce a developmentally competent egg and embryo, it is not surprising that maternal gene products are not only essential for normal embryonic development but also for fertility. This review provides an overview of fundamental aspects of oocyte and early embryonic development and the interference and genetic approaches that have provided access to maternally regulated aspects of vertebrate development. Some of the pathways and molecules highlighted in this review, in particular, Bmps, Wnts, small GTPases, cytoskeletal components, and cell cycle regulators, are well known and are essential regulators of multiple aspects of animal development, including oogenesis, early embryogenesis, organogenesis, and reproductive fitness of the adult animal. Specific examples of developmental processes under maternal control and the essential proteins will be explored in each chapter, and where known conserved aspects or divergent roles for these maternal regulators of early vertebrate development will be discussed throughout this review. Table of Contents: Introduction / Oogenesis: From Germline Stem Cells to Germline Cysts / Oocyte Polarity and the Embryonic Axes: The Balbiani Body, an Ancient Oocyte Asymmetry / Preparing Developmentally Competent Eggs / Egg Activation / Blocking Polyspermy / Cleavage/ Mitosis: Going Multicellular / Maternal-Zygotic Transition / Reprogramming: Epigenetic Modifications and Zygotic Genome Activation / Dorsal-Ventral Axis Formation before Zygotic Genome Activation in Zebrafish and Frogs / Maternal TGF-β and the Dorsal-Ventral Embryonic Axis / Maternal Control After Zygotic Genome Activation / Compensation by Stable Maternal Proteins / Maternal Contributions to Germline Establishment or Maintenance / Perspective / Acknowledgments / References

Current Topics in Developmental Biology series highlights new advances in the field, with this new volume presenting interesting chapters. Each chapter is written by one or more members of an international board of authors. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in the Current Topics in Developmental Biology series Includes the latest information on maternal effect genes in development

The early embryo has emerged as the focal point for analysis of the regulation of gene expression for several reasons. First, the fact that embryogenesis is under genetic control has been appreciated from the earliest days of classical embryology. When experimental techniques became available it was therefore logical that they should be applied to the embryo. With each new advance in methodology, interest in embryonic gene expression studies has increased. Second, many embryos offer unique opportunities for the investigation of specific aspects of the regulation of gene expression. Several phenomena--eg. , control of translation--can be very conveniently studied in a variety of marine invertebrate embryos. Those embryos contain large stores of maternally inherited mRNA which are translated in a highly ordered fashion during specific stages of post fertilization development. Marine invertebrate eggs can be conveniently artifically inseminated and labeled with radioactive precursors. Their analysis is leading to important insights into the mechanisms which regulate gene expression at post-transcriptional levels. Third, recent advances in both transmission and recombinant DNA genetics, especially in organisms such as Drosophila, are providing special opportunities for the analysis of regulatory mechanisms which operate at the level of the genome. Specific genes have been identified, isolated, and--in some instances--sequenced. The opportunity is now available to study the regulation of the expression of single genes in a vertical fashion--from the primary sequence of the gene to the tissues and organs which are the products of morphogenesis.

Providing expert coverage of all major events in early embryogenesis and the organogenesis of specific systems, and supplemented with representative clinical syndromes, Principles of Developmental Genetics, Second Edition discusses the processes of normal development in embryonic and prenatal animals, including humans. The new edition of this classic work supports clinical researchers developing future therapies with its all-new coverage of systems biology, stem cell biology, new technologies, and clinical disorders. A crystal-clear layout, exceptional full-color design, and bulleted summaries of major takeaways and clinical pathways assist comprehension and readability of the highly complex content. All-new coverage of systems biology and stem cell biology in context of evolving technologies places the work squarely on the modern sciences Chapters are complemented with a bulleted summary for easy digestion of the major points, with a clinical summary for therapeutic application Clinical highlights provides a bridge between basic developmental biology and clinical sciences in embryonic and prenatal syndromes

The form and function of every living organism on the earth depends on the complex regulation of gene expression. This is carried out by controlling and interdigitating spatial and temporal patterns of gene activity during the life time of eukaryotic organisms. This is most dramatically apparent during early stages of development, when new types of cells and organs are being formed, often during very short time spans. To achieve this, it is vital that developmentally important genes can be kept in inactive or active states which are stably inherited in the soma. Indeed, it is now wellknown that the propen sity for a gene to be transcribed or silenced is stably propagated through many cell generations, even from parent to progeny. This phenomenon constitutes a type of extragenetic or epigenetic memory of cell identity and developmental potential which has been fundamental to the evolution of complex lifeforms, such as the reader of this book. This monograph focuses on a particular aspect of the epigenetic control of gene function: genomic imprinting. This defines a phenomenon where some genes or whole chromosomes can be silenced, activated, or even deleted depending on their parental origin. The impact of genomic imprinting is most clearly seen in the areas of cancer, clinical genetics, and development. Many of the processes associated with genomic imprinting can be observed in plants, yeast and man, for example, and may constitute, therefore, principles which are very conserved on an evolutionary scale.

The beginning of life may be a miracle to some, and a mystery to others, but it is certainly one of the most exciting and perhaps controversial fields of scientific investigation in the 21st century. Among the metazoa, life begins when an egg is fertilized by a sperm. The sperm provides a genetic blueprint from the father and perhaps some critical proteins. The egg provides a genetic blueprint from the mother together with a large reservoir of mRNAs and proteins that are required for DNA replication, cell division and the onset of zygotic gene expression. All of the thousands of genes in these two mature gametes are transcriptionally silent and remain so until fertilization. This work focuses on three biological systems, providing the reader with a clear understanding of the current state of affairs, and the ability to identify common principles as well as critical differences that are responsible for beginning the process of animal development. The essays presented will be of practical value to all those who are interested in improving fertilization in vitro, in designing novel methods of contraception, in developing preimplantation genetic diagnosis for various diseases, in cloning animals by transplanting nuclei from adult cells to an enucleated egg, and in the application of embryonic stem cells to curing genetic diseases or replacing damaged tissues. But above all, this volume is offered to those who simply have an insatiable curiosity about life and its beginnings.