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https://www.readbyqxmd.com/read/28904386/skewed-x-inactivation-in-lesch-nyhan-disease-carrier-females
#1
Rosa J Torres, Juan G Puig
X chromosome inactivation (XCI) ratios of normal females can range from a highly skewed ratio of 0:100 to a 50:50 ratio. In several X-linked disorders, female carriers present skewed X inactivation. Hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency is an X-linked disorder. Males are affected and present with the complete Lesch-Nyhan disease (LND) or with a partial phenotype (Lesch-Nyhan variant, LNV). Female carriers are usually asymptomatic. The aim of the present study was to analyze the XCI pattern of HPRT-deficiency carrier females...
September 14, 2017: Journal of Human Genetics
https://www.readbyqxmd.com/read/28883481/early-x-chromosome-inactivation-during-human-preimplantation-development-revealed-by-single-cell-rna-sequencing
#2
Joana C Moreira de Mello, Gustavo R Fernandes, Maria D Vibranovski, Lygia V Pereira
In female mammals, one X chromosome is transcriptionally inactivated (XCI), leading to dosage compensation between sexes, fundamental for embryo viability. A previous study using single-cell RNA-sequencing (scRNA-seq) data proposed that female human preimplantation embryos achieve dosage compensation by downregulating both Xs, a phenomenon named dampening of X expression. Using a novel pipeline on those data, we identified a decrease in the proportion of biallelically expressed X-linked genes during development, consistent with XCI...
September 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28810240/efficient-statistical-method-for-association-analysis-of-x-linked-variants
#3
Heejin Jin, Taesung Park, Sungho Won
BACKGROUND/AIMS: Unlike the gene-poor Y chromosome, the X chromosome contains over 1,000 genes that are essential for viability of cells. Females have 2 X chromosomes, and thus female X-linked gene expression would be expected to be twice that of males. To adjust this imbalance, one of the 2 X-linked genes is often inactivated, and this is known as X-chromosome inactivation (XCI). However, recent studies described that a gene can be nonrandomly selected for inactivation from 2 X-linked genes and that XCI is not observed in some X-linked genes...
August 16, 2017: Human Heredity
https://www.readbyqxmd.com/read/28806168/mapping-the-mouse-allelome-reveals-tissue-specific-regulation-of-allelic-expression
#4
Daniel Andergassen, Christoph P Dotter, Daniel Wenzel, Verena Sigl, Philipp C Bammer, Markus Muckenhuber, Daniela Mayer, Tomasz M Kulinski, Hans-Christian Theussl, Josef M Penninger, Christoph Bock, Denise P Barlow, Florian M Pauler, Quanah J Hudson
To determine the dynamics of allelic-specific expression during mouse development, we analyzed RNA-seq data from 23 F1 tissues from different developmental stages, including 19 female tissues allowing X chromosome inactivation (XCI) escapers to also be detected. We demonstrate that allelic expression arising from genetic or epigenetic differences is highly tissue-specific. We find that tissue-specific strain-biased gene expression may be regulated by tissue-specific enhancers or by post-transcriptional differences in stability between the alleles...
August 14, 2017: ELife
https://www.readbyqxmd.com/read/28766050/unique-xci-evolution-in-tokudaia-initial-xci-of-the-neo-x-chromosome-in-tokudaia-muenninki-and-function-loss-of-xist-in-tokudaia-osimensis
#5
Hideki Zushi, Chie Murata, Shusei Mizushima, Chizuko Nishida, Asato Kuroiwa
X chromosome inactivation (XCI) is an essential mechanism to compensate gene dosage in mammals. Here, we show that XCI has evolved differently in two species of the genus Tokudaia. The Amami spiny rat, Tokudaia osimensis, has a single X chromosome in males and females (XO/XO). By contrast, the Okinawa spiny rat, Tokudaia muenninki, has XX/XY sex chromosomes like most mammals, although the X chromosome has acquired a neo-X region by fusion with an autosome. BAC clones containing the XIST gene, which produces the long non-coding RNA XIST required for XCI, were obtained by screening of T...
August 2, 2017: Chromosoma
https://www.readbyqxmd.com/read/28692038/par-terra-directs-homologous-sex-chromosome-pairing
#6
Hsueh-Ping Chu, John E Froberg, Barry Kesner, Hyun Jung Oh, Fei Ji, Ruslan Sadreyev, Stefan F Pinter, Jeannie T Lee
In mammals, homologous chromosomes rarely pair outside meiosis. One exception is the X chromosome, which transiently pairs during X-chromosome inactivation (XCI). How two chromosomes find each other in 3D space is not known. Here, we reveal a required interaction between the X-inactivation center (Xic) and the telomere in mouse embryonic stem (ES) cells. The subtelomeric, pseudoautosomal regions (PARs) of the two sex chromosomes (X and Y) also undergo pairing in both female and male cells. PARs transcribe a class of telomeric RNA, dubbed PAR-TERRA, which accounts for a vast majority of all TERRA transcripts...
August 2017: Nature Structural & Molecular Biology
https://www.readbyqxmd.com/read/28686623/xist-rna-repeat-e-is-essential-for-ash2l-recruitment-to-the-inactive-x-and-regulates-histone-modifications-and-escape-gene-expression
#7
Minghui Yue, Akiyo Ogawa, Norishige Yamada, John Lalith Charles Richard, Artem Barski, Yuya Ogawa
Long non-coding RNA Xist plays a crucial role in establishing and maintaining X-chromosome inactivation (XCI) which is a paradigm of long non-coding RNA-mediated gene regulation. Xist has Xist-specific repeat elements A-F which are conserved among eutherian mammals, underscoring their functional importance. Here we report that Xist RNA repeat E, a conserved Xist repeat element in the Xist exon 7, interacts with ASH2L and contributes to maintenance of escape gene expression level on the inactive X-chromosome (Xi) during XCI...
July 2017: PLoS Genetics
https://www.readbyqxmd.com/read/28663000/skewed-x-chromosome-inactivation-and-xist-locus-methylation-levels-do-not-contribute-to-the-lower-prevalence-of-parkinson-s-disease-in-females
#8
Amit Sharma, Oliver Kaut, Anna Pavlova, Holger Fröhlich, Ashar Ahmad, Ina Schmitt, Osman El-Maarri, Johannes Oldenburg, Ullrich Wüllner
Parkinson's disease (PD) is a degenerative disorder of the nervous system and the cause of the majority of sporadic cases is unknown. Females are relatively protected from PD as compared with males and linkage studies suggested a PD susceptibility locus on the X chromosome. To determine a putative association of skewed X-chromosome inactivation (XCI) and PD, we examined XCI patterns using a human androgen receptor gene-based assay (HUMARA) and did not identify any association of skewed or random X inactivation with clinical heterogeneity among female PD patients...
September 2017: Neurobiology of Aging
https://www.readbyqxmd.com/read/28582519/x-chromosome-inactivation-in-human-pluripotent-stem-cells-as-a-model-for-human-development-back-to-the-drawing-board
#9
Mieke Geens, Susana M Chuva De Sousa Lopes
BACKGROUND: Human pluripotent stem cells (hPSC), both embryonic and induced (hESC and hiPSC), are regarded as a valuable in vitro model for early human development. In order to fulfil this promise, it is important that these cells mimic as closely as possible the in vivo molecular events, both at the genetic and epigenetic level. One of the most important epigenetic events during early human development is X chromosome inactivation (XCI), the transcriptional silencing of one of the two X chromosomes in female cells...
September 1, 2017: Human Reproduction Update
https://www.readbyqxmd.com/read/28491099/induction-of-pluripotent-stem-cells-from-a-manifesting-carrier-of-duchenne-muscular-dystrophy-and-characterization-of-their-x-inactivation-status
#10
Yuko Miyagoe-Suzuki, Takashi Nishiyama, Miho Nakamura, Asako Narita, Fusako Takemura, Satoru Masuda, Narihiro Minami, Kumiko Murayama, Hirofumi Komaki, Yu-Ichi Goto, Shin'ichi Takeda
Three to eight percent of female carriers of Duchenne muscular dystrophy (DMD) develop dystrophic symptoms ranging from mild muscle weakness to a rapidly progressive DMD-like muscular dystrophy due to skewed inactivation of X chromosomes during early development. Here, we generated human induced pluripotent stem cells (hiPSCs) from a manifesting female carrier using retroviral or Sendai viral (SeV) vectors and determined their X-inactivation status. Although manifesting carrier-derived iPS cells showed normal expression of human embryonic stem cell markers and formed well-differentiated teratomas in vivo, many hiPS clones showed bi-allelic expression of the androgen receptor (AR) gene and loss of X-inactivation-specific transcript and trimethyl-histone H3 (Lys27) signals on X chromosomes, suggesting that both X chromosomes of the hiPS cells are in an active state...
2017: Stem Cells International
https://www.readbyqxmd.com/read/28408975/x-chromosome-inactivation-new-players-in-the-initiation-of-gene-silencing
#11
REVIEW
Ines Pinheiro, Edith Heard
X chromosome inactivation (XCI) is a dosage compensation process that was adopted by female mammals to balance gene dosage between XX females and XY males. XCI starts with the upregulation of the non-coding RNA Xist, after which most X-linked genes are silenced and acquire a repressive chromatin state. Even though the chromatin marks of the inactive X have been fairly well described, the mechanisms responsible for the initiation of XCI remain largely unknown. In this review, we discuss recent developments that revealed unexpected factors playing a role in XCI and that might be of crucial importance to understand the mechanisms responsible for the very first steps of this chromosome-wide gene-silencing event...
2017: F1000Research
https://www.readbyqxmd.com/read/28401797/the-state-of-skewed-x-chromosome-inactivation-is-retained-in-the-induced-pluripotent-stem-cells-from-a-female-with-hemophilia-b
#12
Cuicui Lyu, Jun Shen, Jianping Zhang, Feng Xue, Xiaofan Liu, Wei Liu, Rongfeng Fu, Liyan Zhang, Huiyuan Li, Donglei Zhang, Xiaobing Zhang, Tao Cheng, Renchi Yang, Lei Zhang
Skewed X chromosome inactivation (XCI) is a rare reason for hemophilia B in females. It is indefinite whether X chromosome reactivation (XCR) would occur when cells of hemophilia B patients with skewed XCI were reprogrammed into induced pluripotent stem cells (iPSCs). In this study, we investigated a female hemophilia B patient with a known F9 gene mutation: c.676C>T, p.Arg226Trp. We demonstrated that skewed XCI was the pathogenesis of the patient, and we successfully generated numerous iPSC colonies of the patient from peripheral blood mononuclear cells (PBMNCs), which was the first time for generating hemophilia-specific iPSCs from PBMNCs...
July 1, 2017: Stem Cells and Development
https://www.readbyqxmd.com/read/28394482/familial-cases-and-male-cases-with-mecp2-mutations
#13
Qingping Zhang, Ying Zhao, Xinhua Bao, Jinjun Luo, Xiaoying Zhang, Jiarui Li, Liping Wei, Xiru Wu
This is the first report of Chinese familial cases with Rett syndrome (RTT) or X-linked mental retardation (XLMR). RTT is a neurodevelopmental disorder that almost exclusively affects females. Most RTT cases are sporadic. We have studied eight cases with MECP2 mutations in six Chinese families, including three females and five males with RTT or XLMR. All shared identical MECP2 mutations with their mothers. The three females fulfilled the diagnostic criteria for RTT, while the five males were XLMR. A random X-chromosome inactive (XCI) pattern was seen in all the three female patients and two mothers while a skewed XCI in the rest four mothers...
June 2017: American Journal of Medical Genetics. Part B, Neuropsychiatric Genetics
https://www.readbyqxmd.com/read/28387970/mutation-of-the-xist-gene-upregulates-expression-of-x-linked-genes-but-decreases-the-developmental-rates-of-cloned-male-porcine-embryos
#14
Yang Yang, Dan Wu, Dewu Liu, Junsong Shi, Rong Zhou, Xiaoyan He, Jianping Quan, Gengyuan Cai, Enqin Zheng, Zhenfang Wu, Zicong Li
XIST is an X-linked, non-coding gene responsible for the cis induction of X-chromosome inactivation (XCI). Knockout of the XIST allele on an active X chromosome abolishes erroneous XCI and enhances the in vivo development of cloned mouse embryos by more than 10-fold. This study aimed to investigate whether a similar manipulation would improve cloning efficiency in pigs. A male, porcine kidney cell line containing an EGFP insert in exon 1 of the XIST gene, resulting in a knockout allele (XIST-KO), was generated by homologous recombination using transcription activator-like effector nucleases (TALENs)...
April 7, 2017: Molecular Reproduction and Development
https://www.readbyqxmd.com/read/28371302/functional-monosomy-of-6q27-qter-and-functional-disomy-of-xpter-p22-11-due-to-x-6-translocation-with-an-atypical-x-inactivation-pattern
#15
Anna Podolska, Albrecht Kobelt, Sigrid Fuchs, Karl Hackmann, Andreas Rump, Evelin Schröck, Kerstin Kutsche, Nataliya Di Donato
Pattern of X chromosome inactivation (XCI) is typically random in females. However, chromosomal rearrangements affecting the X chromosome can result in XCI skewing due to cell growth disadvantage. In case of an X;autosome translocation, this usually leads to an XCI pattern of 100:0 with the derivative X being the active one in the majority of females. A de novo balanced X;6 translocation [46,X,t(X;6)(p22.1;q27)] and a completely skewed XCI pattern (100:0) were detected in a female patient with microcephaly, cerebellar vermis hypoplasia, heart defect, and severe developmental delay...
May 2017: American Journal of Medical Genetics. Part A
https://www.readbyqxmd.com/read/28368037/high-resolution-rna-allelotyping-along-the-inactive-x-chromosome-evidence-of-rna-polymerase-iii-in-regulating-chromatin-configuration
#16
Ru Hong, Bingqing Lin, Xinyi Lu, Lan-Tian Lai, Xin Chen, Amartya Sanyal, Huck-Hui Ng, Kun Zhang, Li-Feng Zhang
We carried out padlock capture, a high-resolution RNA allelotyping method, to study X chromosome inactivation (XCI). We examined the gene reactivation pattern along the inactive X (Xi), after Xist (X-inactive specific transcript), a prototype long non-coding RNA essential for establishing X chromosome inactivation (XCI) in early embryos, is conditionally deleted from Xi in somatic cells (Xi(∆Xist)). We also monitored the behaviors of X-linked non-coding transcripts before and after XCI. In each mutant cell line, gene reactivation occurs to ~6% genes along Xi(∆Xist) in a recognizable pattern...
April 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28320934/allele-specific-non-cg-dna-methylation-marks-domains-of-active-chromatin-in-female-mouse-brain
#17
Christopher L Keown, Joel B Berletch, Rosa Castanon, Joseph R Nery, Christine M Disteche, Joseph R Ecker, Eran A Mukamel
DNA methylation at gene promoters in a CG context is associated with transcriptional repression, including at genes silenced on the inactive X chromosome in females. Non-CG methylation (mCH) is a distinct feature of the neuronal epigenome that is differentially distributed between males and females on the X chromosome. However, little is known about differences in mCH on the active (Xa) and inactive (Xi) X chromosomes because stochastic X-chromosome inactivation (XCI) confounds allele-specific epigenomic profiling...
April 4, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28316128/skewed-x-chromosome-inactivation-plays-a-crucial-role-in-the-onset-of-symptoms-in-carriers-of-becker-muscular-dystrophy
#18
Emanuela Viggiano, Esther Picillo, Manuela Ergoli, Alessandra Cirillo, Stefania Del Gaudio, Luisa Politano
BACKGROUND: Becker muscular dystrophy (BMD) is an X-linked recessive disorder affecting about 1:18,000 male births. Female carriers are usually asymptomatic, but 2.5-18% may present muscle or heart symptoms. In the present work the role of the X chromosome inactivation (XCI) on the onset of symptoms in BMD carriers was analysed and compared with the pattern observed in Duchenne muscular dystrophy (DMD) carriers. METHODS: XCI was determined on the lymphocytes of 36 BMD carriers - both symptomatic and not symptomatic - from 11 families requiring genetic advice at the Cardiomyology and Medical Genetics of the Second University of Naples, through the AR methylation-based assay...
March 18, 2017: Journal of Gene Medicine
https://www.readbyqxmd.com/read/28315662/insights-into-the-establishment-of-chromatin-states-in-pluripotent-cells-from-studies-of-x-inactivation
#19
REVIEW
Andreas Postlmayr, Anton Wutz
Animal development entails the sequential and coordinated specialization of cells. During cell differentiation, transcription factors, cell signaling pathways, and chromatin-associated protein complexes cooperate in regulating the expression of a large number of genes. Here, we review the present understanding of the establishment of chromatin states by focusing on X chromosome inactivation (XCI) as a model for facultative heterochromatin formation in female embryonic cells. The inactive X chromosome is large enough to be investigated by biochemical and microscopy techniques...
May 19, 2017: Journal of Molecular Biology
https://www.readbyqxmd.com/read/28257137/novel-players-in-x-inactivation-insights-into-xist-mediated-gene-silencing-and-chromosome-conformation
#20
REVIEW
Simão T da Rocha, Edith Heard
The nuclear long noncoding RNA (lncRNA) Xist ensures X-chromosome inactivation (XCI) in female placental mammals. Although Xist is one of the most intensively studied lncRNAs, the mechanisms associated with its capacity to trigger chromosome-wide gene silencing, the formation of facultative heterochromatin and an unusual 3D conformation of the inactive X chromosome (Xi) have remained elusive. Now researchers have identified novel functional partners of Xist in a series of breakthrough studies, using unbiased techniques to isolate Xist-bound proteins, as well as forward genetic screens...
March 3, 2017: Nature Structural & Molecular Biology
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