X Chromosome Inactivation
DOWNLOAD
Download X Chromosome Inactivation PDF/ePub or read online books in Mobi eBooks. Click Download or Read Online button to get X Chromosome Inactivation book now. This website allows unlimited access to, at the time of writing, more than 1.5 million titles, including hundreds of thousands of titles in various foreign languages. If the content not found or just blank you must refresh this page
Females Are Mosaics
DOWNLOAD
Author : Barbara Migeon
language : en
Publisher: Oxford University Press
Release Date : 2007-03-15
Females Are Mosaics written by Barbara Migeon and has been published by Oxford University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007-03-15 with Medical categories.
Women can be described as genetic mosaics because they have two distinctly different types of cells throughout their bodies. Unlike males, who have one X chromosome (inherited from their mother), females have two X chromosomes in every cell (one from each parent). The fathers copy works in some cells, while the mothers copy works in others. These two X chromosomes often function differently, especially if one carries a defective gene. Much has been written about the Y chromosome and its role in inducing maleness. This will be the first book about the X chromosome as a key to female development and the role of X-related factors in the etiology of sex differences in human disease. Barbara Migeon, from the renowned McKusick-Nathan Institute at Johns Hopkins, is a major figure in clinical genetics and is eminently qualified to write this book, and she writes clearly and effectively. She describes both the underlying molecular mechanisms and the remarkable genetic consequences of X inactivation and its role in determining the biological concepts characteristic of women. Females are Mosaics will be valuable to geneticists, biologists, and all health professionals interested in women's health.
X Chromosome Inactivation
DOWNLOAD
Author : Takashi Sado
language : en
Publisher:
Release Date : 2018
X Chromosome Inactivation written by Takashi Sado and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with Electronic books categories.
This book details recently developed technologies and conventionally employed cytological proceduresfor the study of X-Chromosome Inactivation. Chapters detail live imaging, bioinformatic methods, fluorescence in situ hybridization, and immunofluorescence, and procedures to optimize the study of molecular mechanism underlying X chromosome inactivation. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, X-Chromosome Inactivation: Methods Protocols aims to be useful for researchers in the field of epigenetics, chromatin, noncoding RNA, and nuclear architecture.
X Inactivation In Human Females
DOWNLOAD
Author : Pamela Foss Williams
language : en
Publisher:
Release Date : 1977
X Inactivation In Human Females written by Pamela Foss Williams and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1977 with Sex chromosomes categories.
Epigenetics In Human Reproduction And Development
DOWNLOAD
Author : Naumova Anna K
language : en
Publisher: World Scientific
Release Date : 2016-12-20
Epigenetics In Human Reproduction And Development written by Naumova Anna K and has been published by World Scientific this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-12-20 with Medical categories.
Epigenetics is defined as heritable changes that do not affect the DNA sequence but influence gene expression. Epigenetic changes occur at the levels of DNA, histone, protein, and chromatin structures. Proper epigenetic modifications are essential for cell differentiation and function during development, while some epigenetic modifications are passed on from parents to offspring through gametes. Therefore, alterations of epigenetic states would have serious consequences for human development and health. This realization and the advent of new technologies have encouraged the advance of epigenetic studies in recent years. Nonetheless, many aspects of epigenetics, such as regulatory mechanisms and evolutional advantages, remain to be better understood. Written by 26 scientists at the forefront of epigenetics research, this book discusses the different facets of epigenetics: from gametogenesis to child development, as well as from mechanistic studies in animal models to reviews of human clinical data.
Elucidation Of Initiation And Maintenance Mechanisms Of X Chromosome Inactivation
DOWNLOAD
Author : Alissa Minkovsky
language : en
Publisher:
Release Date : 2013
Elucidation Of Initiation And Maintenance Mechanisms Of X Chromosome Inactivation written by Alissa Minkovsky and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
X chromosome inactivation is a program of gene silencing on one of two female mammalian X chromosomes to equalize X-linked gene expression to XY male counterparts. This developmentally-regulated chromatin change is initiated on either the maternal or paternal X chromosome early in embryonic development and, once established, is maintained on the chosen chromosome for the lifetime of the female. The onset of X chromosome inactivation is regulated by the long noncoding transcript Xist and an open question is the field is how embryonic developmental cues trigger expression of Xist and onset of X chromosome inactivation. The correlation of pluripotency with repression of Xist in the mouse system has led to a model where pluripotency transcription factors repress X chromosome inactivation by binding to a region within the first intron of Xist gene. Thus differentiation would release the repression of Xist. We rigorously tested this intron1 hypothesis in a transgenic mouse model and refute that intron1 binding is responsible for the developmental regulation of X chromosome inactivation. A second set of studies focused on the maintenance phase of X chromosome inactivation with the goal of discovering novel chromatin factors that contribute to the remarkable stability of gene silencing on the entire X chromosome. We took an unbiased screening approach, designing a high throughput assay with primary mouse cells bearing reporters on the inactive X, and screened genome-wide siRNA and chemical libraries. We report that knockdown of chromatin-associated protein Atf7ip or its previously characterized interactors reactivates silenced genes of the inactive X chromosome. From chemical screening, we found that the compound Resveratrol can lead to reactivation of silenced genes as part of a novel drug combination. We show evidence that Resveratrol inhibits the dNTP biosynthetic enzyme ribonucleotide reductase in this context. This finding has spurred a collaboration investigating Resveratrol as part of a rationale drug combination for cancer therapy. In summary, these studies demonstrate that X chromosome inactivation is powerful and flexible model for the interrogation of mammalian chromatin regulation mechanisms with relevance for disease therapy.
Investigating X Chromosome Inactivation
DOWNLOAD
Author : Sonja Pritchett
language : en
Publisher: LAP Lambert Academic Publishing
Release Date : 2011-01
Investigating X Chromosome Inactivation written by Sonja Pritchett and has been published by LAP Lambert Academic Publishing this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011-01 with categories.
Females have two alleles for each gene on the X- chromosome, whereas males have only one. This inequality is balanced by X-chromosome inactivation (XCI). This process transcriptionally silences one X- chromosome in every female cell. The choice of which X-chromosome should be "turned-o " is considered to be random. Studies on mice have revealed that a locus on the X-chromosome, the X controlling element (Xce), signi cantly in uences the choice of which X- chromosome is inactivated. Renault et al. (2007) studied a family of which many of the females exhibit symptoms of the X-linked recessive disease, Haemophilia A. The XCI ratios of the women in this family were signi cantly di erent from what would be expected if the XCI process was random. This studies result is consistent with the human XCE hypothesis. Random and genetic models of XCI ratios are investigated here in theory and are compared to a sample of XCI ratios. Using goodness-of- fit testing, it is determined which models best fit the data. Anderson-Darling statistics and visual inspection of graphics suggest that a three allele genetic model is a good fit to the data, supporting the human XCE hypothesis.
Investigation Of X Chromosome Inactivation
DOWNLOAD
Author : Susan Carole Lester
language : en
Publisher:
Release Date : 1982
Investigation Of X Chromosome Inactivation written by Susan Carole Lester and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1982 with Gene expression categories.
Studies Of Human X Chromosome Inactivation
DOWNLOAD
Author : Carolyn Janet.* Brown
language : en
Publisher:
Release Date : 1991
Studies Of Human X Chromosome Inactivation written by Carolyn Janet.* Brown and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1991 with categories.
Role Of Xist Ribonucleic Acid In The Maintenance Of X Chromosome Inactivation
DOWNLOAD
Author : Györgyi Csankovszki
language : en
Publisher:
Release Date : 2001
Role Of Xist Ribonucleic Acid In The Maintenance Of X Chromosome Inactivation written by Györgyi Csankovszki and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with categories.
The role of Xist RNA in silencing the inactive X of female somatic cells was investigated by generating a conditional allele of the Xist gene. A system was set up in which reactivation of two X-linked genes, the endogenous Hprt gene and an X-linked GFP transgene, can be quantitatively assessed. Mouse embryonic fibroblasts derived from mice carrying the conditional Xist mutation were cultured and infected with an adenovirus vector carrying the gene for Cre recombinase. After Cre mediated deletion of Xist, the inactive X remained transcriptionally silent, late replicating, and hypoacetylated on histone H4, confirming that X-inactivation can be maintained in the absence of Xist RNA. However, the Xist mutant inactive X was no longer enriched in histone macroH2A 1. Furthermore, the reactivation rate of GFP and Hprt increased, indicating Xist RNA does contribute to gene repression on the inactive X. DNA methylation, histone hypoacetylation and Xist RNA were found to act synergistically in X chromosome silencing. To investigate whether Xist RNA can also silence the active X chromosome of male somatic cells, Xist expression on the active X was induced by demethylation. Demethylation was achieved by Cre mediated deletion of a conditional mutant allele of DNA methyltransferase-l (Dnmtl) in male fibroblasts. In these cells, Xist RNA coated the active X chromosome, in a pattern indistinguishable from coating of the inactive X of female cells. Although many Xist expressing chromosomes also transcribed X-linked genes Pgk-i and Hprt, in a small percent of cells Xist expression led to X chromosome inactivation. The proportion of chromosome expressing X-linked genes declined, and occasionally the X became late replicating, indicating that X-inactivation can be initiated in male somatic cells.
The Role Of Specific Elements In X Chromosome Inactivation And Maintenance Of The Inactive X Chromosome
DOWNLOAD
Author : Andrea Mae Yoest
language : en
Publisher:
Release Date : 2021
The Role Of Specific Elements In X Chromosome Inactivation And Maintenance Of The Inactive X Chromosome written by Andrea Mae Yoest and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with Biology categories.
XCI is a form of dosage compensation that is established in early development of female mammals where one X chromosome is randomly silenced, thus balancing expression of X-linked genes. XCI is achieved by many cis- and trans- elements that establish and maintain silenced gene expression from the Xi. Molecular biologists have used the Xi as a model to study the maintenance of chromosome-wide gene silencing throughout development. Here, we used gene sequencing technology to examine the effects of gene expression after the loss of a cis-acting non-coding RNA called XIST. We found that one out of 24 X-linked genes had some expression from the Xi after the XIST promoter was deleted from the Xi, indicating reactivation or escape from XCI. Most of the genes we examined reside on the short arm of the X, or Xp. Xp is not part of the ancestral X chromosome and was acquired more recently than the long arm, or Xq. Xp has adapted to XCI and as such may be more prone to reactivation. However, our results mostly disagree with this evolutionary hypothesis. This indicates that the establishment of silenced genes on the Xi is initiated by XIST, however XIST may not be necessary for maintenance of this silent state. This is also indicative that there are other factors maintaining the silenced state on the p arm and the loss of XIST expression is not critical to keep the expression off. We are also able to visualize the Xi territory in single cells through microscopy due to its chromosome-wide heterochromatic state. There are known proteins, including SMCHD1 and LRIF1, that localize to the Xi territory in human cells. We attempted to connect their function to the physical properties and chromatin organization of the Xi. Previous data show that SMCHD1 has some function in the maintenance of small-scale TADs on the Xi and LRIF1, while more elusive, colocalizes to the Xi. We also examined how loss of a large macrosatellite region known to be involved in large-scale structure of the Xi, DXZ4, changes the compaction of the Xi territory in cells. We measured the Xi volume and arrangement of specific chromatin modifications in single cells. We observed an increase in volume in cells without LRIF1, SMCHD1, DXZ4, or a combination of two indicating their respective roles in maintaining small structure and superstructure on the Xi. However, we did not observe significant changes to incorporation of chromatin modifications, meaning the loss of one or two of these elements does not change the spread, or arrangement, of heterochromatic markers on the Xi.