Author: William Francis Mueller
Publisher:
ISBN: 9781303001017
Category :
Languages : en
Pages : 176
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Book Description
Human genes are split into regions that code for protein, exons, and regions that don't, introns. Upon transcription, the removal of these intervening introns is necessary if a usable mRNA molecule is to be translated. The process of intron removal and subsequent ligation of exons is called splicing and is carried out by a large complex called the spliceosome. This process is driven by sequence elements within the pre-mRNA itself and is the major contributor of diversity to the human transcriptome. Due to the ubiquitous nature of alternative splicing in almost every multi-exon gene, the regulation pathways of exon inclusion are a subject of wide study The different lengths of introns and exons as well as location of splice sites in a pre-mRNA molecule have been shown to have differing affects on the spliceosomes ability to recognize them. Using \emph{in vitro} splicing and complex formation assays in parallel with cell transfection experiments, we determined that the distance between two splice sites across the intron or across the exon are strong predictors of splice site usage. Additionally, we found that two splice sites interact differently when placed at different lengths apart. Our findings suggest a mechanism for observed selection of specific intron/exon architectures. Splice site recognition is also influenced by the presence of protein binding sequence elements in the pre-mRNA that alter spliceosomal recruitment. Previously, these proteins and sequence elements had been rigidly classified into splice enhancing or inhibiting categories. We show that this rigid classification is incorrect. We found that the location of these elements relative to the splice site determines their enhancing or silencing effect. That is, an enhancing element found upstream of a splice site imposes a silencing effect when relocated downstream of the splice site (and vice versa). Spliceosomal proteins are conserved from yeast to humans. The sequence elements used in pre-mRNA sequences have been evolving over time but under pressure from multiple cellular processes, including splicing. To observe the effect of splicing on evolution, we took advantage of the synonymous mutation positions that are under the least amount of selective pressure from the genetic code. We mutated these positions and found that some caused a large decrease in exon inclusion. When we analyzed the comparative alignment data, we found that these specific nucleotide mutations were selected against across species in order to maintain exon inclusion. SNP analysis showed that this pattern of selection was broadly observable at synonymous positions throughout the human genome.
Author: Stefan Stamm
Publisher: John Wiley & Sons
ISBN: 3527647988
Category : Science
Languages : en
Pages : 660
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Book Description
This book was written for graduate and medical students, as well as clinicians and postdoctoral researchers. It describes the theory of alternative pre-mRNA splicing in twelve introductory chapters and then introduces protocols and their theoretical background relevant for experimental research. These 43 practical chapters cover: Basic methods, Detection of splicing events, Analysis of alternative pre-mRNA splicing in vitro and in vivo, Manipulation of splicing events, and Bioinformatic analysis of alternative splicing. A theoretical introduction and practical guide for molecular biologists, geneticists,clinicians and every researcher interested in alternative splicing. Website: www.wiley-vch.de/home/splicing
Author: B. D. Hames
Publisher: Oxford University Press, USA
ISBN:
Category : Music
Languages : en
Pages : 238
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Book Description
This book gives a co-ordinated review of our present knowledge of eukaryotic RNA synthesis.
Author: Rosanna Asselta
Publisher: Frontiers Media SA
ISBN: 2889662357
Category : Science
Languages : en
Pages : 197
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Book Description
This eBook is a collection of articles from a Frontiers Research Topic. 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 Office: frontiersin.org/about/contact.
Author: Edward Frank Modafferi
Publisher:
ISBN:
Category :
Languages : en
Pages : 238
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Book Description
Author: Benjamin J. Blencowe
Publisher: Springer Science & Business Media
ISBN: 9780387773735
Category : Medical
Languages : en
Pages : 260
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Book Description
Yet again Springer has reached the market before everyone. This is the first book that is solely dedicated to the topic of alternative splicing. The book contains chapters by experts in the field that cover nearly all aspects of this hugely important subject. The purpose of the text is to provide a single, authoritative source of information on alternative splicing that is accessible to researchers in diverse fields. It is suitable for beginners and experts alike.
Author: Philippe Jeanteur
Publisher: Springer Science & Business Media
ISBN: 3662097281
Category : Science
Languages : en
Pages : 254
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Book Description
The discovery in 1977 that genes are split into exons and introns has done away with the one gene - one protein dogma. Indeed, the removal of introns from the primary RNA transcript is not necessarily straightforward since there may be optional pathways leading to different messenger RNAs and consequently to different proteins. Examples of such an alternative splicing mechanism cover all fields of biology. Moreover, there are plenty of occurrences where deviant splicing can have pathological effects. Despite the high number of specific cases of alternative splicing, it was not until recently that the generality and extent of this phenomenon was fully appreciated. A superficial reading of the preliminary sequence of the human genome published in 2001 led to the surprising, and even deceiving to many scientists, low number of genes (around 32,000) which contrasted with the much higher figure around 150,000 which was previously envisioned. Attempts to make a global assessment of the use of alternative splicing are recent and rely essentially on the comparison of genomic mRNA and EST sequences as reviewed by Thanaraj and Stamm in the first chapter of this volume. Most recent estimates suggest that 40-60% of human genes might be alternatively spliced, as opposed to about 22% for C. elegans.
Author: Scott Adamson
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Alternative splicing is a key process in higher eukaryotes in which different introns in pre-mRNA are removed to generate diversity in mature RNA products. Changes in alternative splicing are important under normal conditions for expanding the proteome and regulating RNA species, however splicing dysregulation can underlie monogenic and polygenic diseases. Understanding the connection between genetic variants and phenotypes is a major goal of personalized medicine and is key to understanding the underlying biological processes. Here I develop a novel highthroughput splicing reporter assay to elucidate the impact of genetic variants on pre-mRNA splicing efficiency called variant exon sequencing (Vex-seq). The utility of Vex-seq is first demonstrated in the context of thousands of variants found in the human population across 110 exons, then it is applied to understand the sequence determinants of splicing regulatory elements. These splicing regulatory elements were identified by examining ENCODE data which monitors RNA-protein interactions, and changes in splicing upon RNA binding protein (RBP) knockdown. Vex-seq is used to identify sequence features associated with RBP-specific splicing regulation and contribute to our understanding of a key, understudied mechanistic link between sequence variation and splicing regulation.
Author: Peter Scheiffele
Publisher: Springer Nature
ISBN: 1071625217
Category : Science
Languages : en
Pages : 356
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Book Description
This detailed volume collects commonly used and cutting-edge methods to analyze alternative splicing, a key step in gene regulation. After an introduction of the alternative splicing mechanism and its targeting for therapeutic strategies, the book continues with techniques for analyzing alternative splicing profiles in complex biological systems, visualizing and localizing alternative spliced transcripts with cellular and sub-cellular resolution, probing regulators of alternative splicing, as well as assessing the functional consequences of alternative splicing. Written for the highly successful Methods in Molecular Biology series, chapters include introduction to their respective topics, lists of the necessary materials and reagents, step-by-step, reproducible protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and practical, Alternative Splicing: Methods and Protocols serves as an ideal guide for both RNA aficionados that want to implement novel approaches in their labs and novices undertaking alternative splicing projects.
Author: Angela Norie Brooks
Publisher:
ISBN:
Category :
Languages : en
Pages : 236
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Book Description
A majority of metazoan genes contain introns in their primary transcripts (pre-mRNA) that require removal by the spliceosome--a cellular complex composed of protein and RNA. Upon removal of introns from the primary transcript, the remaining exonic portion of the transcript is spliced together. It is essential to remove the correct intronic portion of a primary transcript in order to produce the desired product, typically a protein-coding mRNA. Pre-mRNAs are alternatively spliced when different intron boundaries are used by the spliceosome, thus creating different mRNA products. Alternative splicing allows for an additional step of gene regulation by producing transcript isoforms that can be differentially processed in a particular tissue or developmental time point. Alternative splicing is primarily regulated by RNA binding proteins that bind to pre-mRNA and act to recruit or inhibit the spliceosome at specific splice sites. A central aim of this work is to gain a better understanding of splicing regulation by the identification and characterization of protein regulators of splicing and cis-acting splicing regulatory sequences in the model organism, Drosophila melanogaster. To identify splicing regulatory elements, many previous studies in vertebrate genomes have used computational methods. In collaboration with Anna I. Podgornaia, I applied such an approach to predict splicing regulatory elements in Drosophila melanogaster and compared them with elements found in vertebrates. I identified 330 putative splicing enhancer sequences enriched near weak 5' and 3' splice sites of constitutively spliced introns. I found that a significant proportion (58%) of D. melanogaster enhancers were previously reported as splicing enhancers in vertebrates. To provide additional evidence for the function of the intronic splicing enhancers (ISEs), I identified intronic hexamers significantly enriched within sequences phylogenetically conserved among 15 insect species. This analysis uncovered 73 putative ISEs that are also enriched in conserved regions of the D. melanogaster genome. The functions of nine enhancer sequences were verified in a heterologous splicing reporter by Julie L. Aspden, demonstrating that these sequences are sufficient to enhance splicing in vivo. Taken together, these data identify a set of predicted positive-acting splicing regulatory motifs in the Drosophila genome and highlight those regulatory sequences that are present in distant metazoan genomes. To identify and characterize splicing regulators, collaborators and I have combined RNAi and RNA-Seq to identify exons that are regulated by 58 known or putative splicing regulators. To identify and quantify alternative splicing events from RNA-Seq data, I developed the JuncBASE (Junction Based Analysis of Splicing Events) software package. For a pilot study, I identified 404 splicing events significantly affected upon depletion of pasilla. Preliminary analysis showed 879 splicing events affected by at least one of the 57 other proteins. The sequence regions upstream and within Pasilla-repressed exons and downstream of Pasilla-activated exons are enriched for YCAY repeats, which is consistent with the location of these motifs near regulated exons of the mammalian ortholog, Nova. Thus, the RNA regulatory map of Pasilla and Nova is highly conserved between insects and mammals despite the fact that the pre-mRNAs that are regulated by Pasilla and Nova are almost entirely non-overlapping. This observation strongly suggests that the regulatory codes of individual RNA binding proteins are nearly immutable, yet the regulatory modules controlled by these proteins are highly evolvable. I also present RNA regulatory maps for the four hnRNP proteins: hrp36, hrp38, hrp40, and hrp48. Lastly, I examine splicing regulation throughout the life cycle of D. melanogaster. Using transcriptome data from 30 developmental time points produced by collaborators from the modENCODE Consortium, I identified a total of 23,859 alternative splicing events in Drosophila, taking into account all transcript information from D. melanogaster annotations, short sequenced reads (Illumina RNA-Seq), sequenced cDNA, long RNA-Seq reads (454 RNA-Seq) from adult flies, and short read sequences of rRNA-depleted RNA from embryonic time points. I observed that 60.7% of intron-containing genes in D. melanogaster are alternatively spliced. Using only the Illumina RNA-Seq reads throughout development, 21,216 splicing events were expressed and 13,951 events were differentially spliced in at least one time point. I also observed exons with similar patterns of splicing changes throughout development as well as sex-biased alternative splicing. Integrating information from our pasilla study, I also observed correlations of pasilla gene expression with alternative splicing changes of its target exons throughout development.
