Nuclear Dynamics

Nuclear Dynamics
Author: Quang Phung
Publisher:
Total Pages: 120
Release: 2009
Genre:
ISBN: 9781109248982

The cell nucleus contains the genetic materials of an organism and allows selective nucleocytoplasmic transport via the nuclear pores embedded in the nuclear membranes. In interphase, importin beta is a well-studied nuclear import receptor mediating the classical nuclear import pathway. In mitosis, importin beta negatively regulates key mitotic events of mitotic spindle formation and nuclear pore assembly. Here, we showed that importin beta directly interacts with ELYS, the pore-targeting protein, and negatively interferes with the initiating step of nuclear pore assembly. We also showed that both Xenopus and human importin beta directly interacts with human centrin2, a small Ca-binding protein involved in centrosomes dynamics as well as protein and mRNA export. While nuclear import of transcription factors into the nucleus is required to initiate gene transcription, mRNA transcripts need to be exported out to the cytoplasm for translation into new proteins. In this study, we showed that both over-expression of human Shd1 and Eny2 causes nuclear accumulation of poly(A)+ RNA, suggesting potential roles in an unknown vertebrate TREX2 in mRNA export. Furthermore, Eny2 was shown to biochemically associate with multiple nuclear transport factors, notably TAP, the major mRNA export receptor. In conclusion, these data provide supporting evidence for a potential vertebrate TREX2 involved in mRNA export.

Regulation of the Assembly and Function of the Nuclear Pore

Regulation of the Assembly and Function of the Nuclear Pore
Author: Valerie Anne Delmar
Publisher:
Total Pages: 122
Release: 2008
Genre:
ISBN:

The nucleus is the defining structure of eukaryotic cells. The nuclear envelope acts as a barrier between nucleus and cytoplasm. Nuclear pore complexes perforating the envelope control all traffic into and out of the nucleus, and thus act to regulate transcription, translation, and other essential cellular processes. During mitosis, the nuclear envelope from flies to mammals disassembles into its component parts, with the nuclear pore breaking into multiple subunits. The pore then reassembles in a step-wise process as the nuclear envelope reforms in late anaphase. The major focus of this thesis has been to better understand the assembly and function of the nuclear pore. It has resulted in three published papers and one paper in preparation. First, I participated, with postdoc Dr. Corine Lau, in a study of the novel vertebrate transmembrane nucleoporin, Ndc1. I resolved the topology of yeast Ndc1p and identified conserved amino acids to target for future functional studies (Chapter 1). In a second study, I participated in a collaboration with the laboratory of Dr. Pamela Silver at Harvard Medical School in identifying a new role for the vertebrate nuclear pore in the regulation of transcription. We found that in vertebrates, specific chromosomal regions move to the nuclear pore complexes during transcriptional activation (Chapter 2). Key work next centered on the mechanism of action of importin beta in negatively regulating nuclear membrane fusion and pore assembly. (The small GTPase, Ran, positively regulates both these processes.) A major unanswered question has been, which specific steps in nuclear pore assembly are regulated by importin beta or RanGTP. I determined, using Xenopus constructs, that importin beta is an authentic regulator of nuclear pore assembly and that, contrary to previously published results, Ran reverses this negative regulation (Chapter 3). Finally, a fourth study, done with Dr. Corine Lau, established that the distant importin beta relative, transportin, also negatively regulates nuclear membrane and pore assembly (Chapter 4). I showed that both transportin and importin beta act early to control the initial step of pore assembly: the binding of the pore-targeting protein ELYS to chromatin, which sets in motion the specific targeting of nuclear pores to the nuclear surface.

The Nucleolus

The Nucleolus
Author: Mark O. J. Olson
Publisher: Springer Science & Business Media
Total Pages: 434
Release: 2011-09-15
Genre: Science
ISBN: 1461405149

Within the past two decades, extraordinary new functions for the nucleolus have begun to appear, giving the field a new vitality and generating renewed excitement and interest. These new discoveries include both newly-discovered functions and aspects of its conventional role. The Nucleolus is divided into three parts: nucleolar structure and organization, the role of the nucleolus in ribosome biogenesis, and novel functions of the nucleolus.

Maternal Control of Development in Vertebrates

Maternal Control of Development in Vertebrates
Author: Florence Louise Marlow
Publisher: Morgan & Claypool Publishers
Total Pages: 221
Release: 2010
Genre: Family & Relationships
ISBN: 161504051X

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

Introduction to Epigenetics

Introduction to Epigenetics
Author: Renato Paro
Publisher: Springer Nature
Total Pages: 215
Release: 2021-03-23
Genre: Science
ISBN: 3030686701

This open access textbook leads the reader from basic concepts of chromatin structure and function and RNA mechanisms to the understanding of epigenetics, imprinting, regeneration and reprogramming. The textbook treats epigenetic phenomena in animals, as well as plants. Written by four internationally known experts and senior lecturers in this field, it provides a valuable tool for Master- and PhD- students who need to comprehend the principles of epigenetics, or wish to gain a deeper knowledge in this field. After reading this book, the student will: Have an understanding of the basic toolbox of epigenetic regulation Know how genetic and epigenetic information layers are interconnected Be able to explain complex epigenetic phenomena by understanding the structures and principles of the underlying molecular mechanisms Understand how misregulated epigenetic mechanisms can lead to disease

Computational Genomics with R

Computational Genomics with R
Author: Altuna Akalin
Publisher: CRC Press
Total Pages: 463
Release: 2020-12-16
Genre: Mathematics
ISBN: 1498781861

Computational Genomics with R provides a starting point for beginners in genomic data analysis and also guides more advanced practitioners to sophisticated data analysis techniques in genomics. The book covers topics from R programming, to machine learning and statistics, to the latest genomic data analysis techniques. The text provides accessible information and explanations, always with the genomics context in the background. This also contains practical and well-documented examples in R so readers can analyze their data by simply reusing the code presented. As the field of computational genomics is interdisciplinary, it requires different starting points for people with different backgrounds. For example, a biologist might skip sections on basic genome biology and start with R programming, whereas a computer scientist might want to start with genome biology. After reading: You will have the basics of R and be able to dive right into specialized uses of R for computational genomics such as using Bioconductor packages. You will be familiar with statistics, supervised and unsupervised learning techniques that are important in data modeling, and exploratory analysis of high-dimensional data. You will understand genomic intervals and operations on them that are used for tasks such as aligned read counting and genomic feature annotation. You will know the basics of processing and quality checking high-throughput sequencing data. You will be able to do sequence analysis, such as calculating GC content for parts of a genome or finding transcription factor binding sites. You will know about visualization techniques used in genomics, such as heatmaps, meta-gene plots, and genomic track visualization. You will be familiar with analysis of different high-throughput sequencing data sets, such as RNA-seq, ChIP-seq, and BS-seq. You will know basic techniques for integrating and interpreting multi-omics datasets. Altuna Akalin is a group leader and head of the Bioinformatics and Omics Data Science Platform at the Berlin Institute of Medical Systems Biology, Max Delbrück Center, Berlin. He has been developing computational methods for analyzing and integrating large-scale genomics data sets since 2002. He has published an extensive body of work in this area. The framework for this book grew out of the yearly computational genomics courses he has been organizing and teaching since 2015.