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https://www.readbyqxmd.com/read/28320934/allele-specific-non-cg-dna-methylation-marks-domains-of-active-chromatin-in-female-mouse-brain
#1
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...
March 20, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28320130/spg2-mimicking-multiple-sclerosis-in-a-family-identified-using-next-generation-sequencing
#2
Anna Rubegni, Carla Battisti, Alessandra Tessa, Alfonso Cerase, Stefano Doccini, Alessandro Malandrini, Filippo M Santorelli, Antonio Federico
Several single gene disorders can potentially be overlooked in the differential diagnostic evaluation of patients with multiple sclerosis (MS). Pelizaeus-Merzbacher disease and spastic paraplegia type 2 are allelic X-linked disorders associated with defective myelination of the central nervous system and mutations in PLP1. Neurological symptoms are occasionally observed in female carriers of these mutations. Two women - the proposita (Pt1) and her mother (Pt2) - reported walking difficulties since adolescence and showed progressive cognitive decline...
April 15, 2017: Journal of the Neurological Sciences
https://www.readbyqxmd.com/read/28315662/insights-into-the-establishment-of-chromatin-states-in-pluripotent-cells-from-studies-of-x-inactivation
#3
REVIEW
Andreas Postlmayr, Anton Wutz
Animal development entails the sequential and coordinated specialisation of cells. During cell differentiation transcription factors, cell signalling 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 (Xi) is large enough to be investigated by biochenical and microscopy techniques...
March 15, 2017: Journal of Molecular Biology
https://www.readbyqxmd.com/read/28302064/a-sibship-with-duplication-of-xq28-inherited-from-the-mother-genomic-characterization-and-clinical-outcomes
#4
Dong Keon Yon, Ji Eun Park, Seung Jun Kim, Sung Han Shim, Kyu Young Chae
BACKGROUND: Loss-of-function mutations in methyl-CpG-binding protein 2 (MECP2; MIM *300005) results in the Rett syndrome, whereas gain-of-function mutations are associated with the MECP2 duplication syndrome. METHODS: We did research on a family with two brothers showing Xq28 duplication syndrome using various molecular cytogenetic techniques such as multiplex ligation-dependent probe amplification and array-based genomic hybridization. RESULTS: The duplicated region had several genes including MECP2 and interleukin-1 receptor associated kinase 1 (IRAK1; MIM *300283)...
March 17, 2017: BMC Medical Genetics
https://www.readbyqxmd.com/read/28257338/expansion-of-the-phenotypic-spectrum-in-three-families-of-methyl-cpg-binding-protein-2-duplication-syndrome
#5
Amita Moirangthem, Moni Tuteja Bhatia, Priyanka Srivastava, Kausik Mandal, Archana Rai, Shubha R Phadke
The methyl CpG-binding protein 2 duplication syndrome (OMIM #300260) is characterized by hypotonia, developmental delay, spasticity, seizures, and recurrent infections. It is fully penetrant in males and the females can have varied manifestations because of skewed X-inactivation. The size of the duplication can range from 0.2 Mb to over 100 Mb. Around 150 cases have been reported in the literature so far. Here, we report the unusual findings in three cases such as hepatomegaly, ataxia and females with mild intellectual disability that further expand the phenotypic spectrum of this disorder...
April 2017: Clinical Dysmorphology
https://www.readbyqxmd.com/read/28257137/novel-players-in-x-inactivation-insights-into-xist-mediated-gene-silencing-and-chromosome-conformation
#6
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
https://www.readbyqxmd.com/read/28238796/ephrin-b1-mosaicism-drives-cell-segregation-in-craniofrontonasal-syndrome-hipsc-derived-neuroepithelial-cells
#7
Terren K Niethamer, Andrew R Larson, Audrey K O'Neill, Marina Bershteyn, Edward C Hsiao, Ophir D Klein, Jason H Pomerantz, Jeffrey O Bush
Although human induced pluripotent stem cells (hiPSCs) hold great potential for the study of human diseases affecting disparate cell types, they have been underutilized in seeking mechanistic insights into the pathogenesis of congenital craniofacial disorders. Craniofrontonasal syndrome (CFNS) is a rare X-linked disorder caused by mutations in EFNB1 and characterized by craniofacial, skeletal, and neurological anomalies. Heterozygous females are more severely affected than hemizygous males, a phenomenon termed cellular interference that involves mosaicism for EPHRIN-B1 function...
March 14, 2017: Stem Cell Reports
https://www.readbyqxmd.com/read/28238550/diverse-non-genetic-allele-specific-expression-effects-shape-genetic-architecture-at-the-cellular-level-in-the-mammalian-brain
#8
Wei-Chao Huang, Elliott Ferris, Tong Cheng, Cornelia Stacher Hörndli, Kelly Gleason, Carol Tamminga, Janice D Wagner, Kenneth M Boucher, Jan L Christian, Christopher Gregg
Interactions between genetic and epigenetic effects shape brain function, behavior, and the risk for mental illness. Random X inactivation and genomic imprinting are epigenetic allelic effects that are well known to influence genetic architecture and disease risk. Less is known about the nature, prevalence, and conservation of other potential epigenetic allelic effects in vivo in the mouse and primate brain. Here we devise genomics, in situ hybridization, and mouse genetics strategies to uncover diverse allelic effects in the brain that are not caused by imprinting or genetic variation...
March 8, 2017: Neuron
https://www.readbyqxmd.com/read/28134930/xist-dependent-imprinted-x-inactivation-and-the-early-developmental-consequences-of-its-failure
#9
Maud Borensztein, Laurène Syx, Katia Ancelin, Patricia Diabangouaya, Christel Picard, Tao Liu, Jun-Bin Liang, Ivaylo Vassilev, Rafael Galupa, Nicolas Servant, Emmanuel Barillot, Azim Surani, Chong-Jian Chen, Edith Heard
The long noncoding RNA Xist is expressed from only the paternal X chromosome in mouse preimplantation female embryos and mediates transcriptional silencing of that chromosome. In females, absence of Xist leads to postimplantation lethality. Here, through single-cell RNA sequencing of early preimplantation mouse embryos, we found that the initiation of imprinted X-chromosome inactivation absolutely requires Xist. Lack of paternal Xist leads to genome-wide transcriptional misregulation in the early blastocyst and to failure to activate the extraembryonic pathway that is essential for postimplantation development...
March 2017: Nature Structural & Molecular Biology
https://www.readbyqxmd.com/read/28132849/non-canonical-and-sexually-dimorphic-x-dosage-compensation-states-in-the-mouse-and-human-germline
#10
Mahesh N Sangrithi, Helene Royo, Shantha K Mahadevaiah, Obah Ojarikre, Leena Bhaw, Abdul Sesay, Antoine H F M Peters, Michael Stadler, James M A Turner
Somatic X dosage compensation requires two mechanisms: X inactivation balances X gene output between males (XY) and females (XX), while X upregulation, hypothesized by Ohno and documented in vivo, balances X gene with autosomal gene output. Whether X dosage compensation occurs in germ cells is unclear. We show that mouse and human germ cells exhibit non-canonical X dosage states that differ from the soma and between the sexes. Prior to genome-wide reprogramming, X upregulation is present, consistent with Ohno's hypothesis...
February 6, 2017: Developmental Cell
https://www.readbyqxmd.com/read/28099951/complex-x-chromosomal-rearrangements-in-two-women-with-ovarian-dysfunction-implications-of-chromothripsis-chromoanasynthesis-dependent-and-independent-origins-of-complex-genomic-alterations
#11
Erina Suzuki, Hirohito Shima, Machiko Toki, Kunihiko Hanew, Keiko Matsubara, Hiroki Kurahashi, Satoshi Narumi, Tsutomu Ogata, Tsutomu Kamimaki, Maki Fukami
Our current understanding of the phenotypic consequences and the molecular basis of germline complex chromosomal rearrangements remains fragmentary. Here, we report the clinical and molecular characteristics of 2 women with germline complex X-chromosomal rearrangements. Patient 1 presented with nonsyndromic ovarian dysfunction and hyperthyroidism; patient 2 exhibited various Turner syndrome- associated symptoms including ovarian dysfunction, short stature, and autoimmune hypothyroidism. The genomic abnormalities of the patients were characterized by array-based comparative genomic hybridization, high-resolution karyotyping, microsatellite genotyping, X-inactivation analysis, and bisulfite sequencing...
2016: Cytogenetic and Genome Research
https://www.readbyqxmd.com/read/28027854/exome-sequencing-in-children-of-women-with-skewed-x-inactivation-identifies-atypical-cases-and-complex-phenotypes
#12
Elisa Giorgio, Alessandro Brussino, Elisa Biamino, Elga Fabia Belligni, Alessandro Bruselles, Andrea Ciolfi, Viviana Caputo, Simone Pizzi, Alessandro Calcia, Eleonora Di Gregorio, Simona Cavalieri, Cecilia Mancini, Elisa Pozzi, Marta Ferrero, Evelise Riberi, Iolanda Borelli, Antonio Amoroso, Giovanni Battista Ferrero, Marco Tartaglia, Alfredo Brusco
BACKGROUND: More than 100 X-linked intellectual disability (X-LID) genes have been identified to be involved in 10-15% of intellectual disability (ID). METHOD: To identify novel possible candidates, we selected 18 families with a male proband affected by isolated or syndromic ID. Pedigree and/or clinical presentation suggested an X-LID disorder. After exclusion of known genetic diseases, we identified seven cases whose mother showed a skewed X-inactivation (>80%) that underwent whole exome sequencing (WES, 50X average depth)...
December 19, 2016: European Journal of Paediatric Neurology: EJPN
https://www.readbyqxmd.com/read/27999427/cancer-genetics-x-inactivation-and-cancer-incidence
#13
Sarah Seton-Rogers
No abstract text is available yet for this article.
December 21, 2016: Nature Reviews. Cancer
https://www.readbyqxmd.com/read/27995571/evaluating-the-feasibility-of-dna-methylation-analyses-using-long-term-archived-brain-formalin-fixed-paraffin-embedded-samples
#14
Stine T Bak, Nicklas H Staunstrup, Anna Starnawska, Tina F Daugaard, Jens R Nyengaard, Mette Nyegaard, Anders Børglum, Ole Mors, Karl-Anton Dorph-Petersen, Anders L Nielsen
We here characterize the usability of archival formalin-fixed paraffin-embedded (FFPE) brain tissue as a resource for genetic and DNA methylation analyses with potential relevance for brain-manifested diseases. We analyzed FFPE samples from The Brain Collection, Aarhus University Hospital Risskov, Denmark (AUBC), constituting 9479 formalin-fixated brains making it one of the largest collections worldwide. DNA extracted from brain FFPE tissue blocks was interrogated for quality and usability in genetic and DNA methylation analyses by different molecular techniques...
December 19, 2016: Molecular Neurobiology
https://www.readbyqxmd.com/read/27989770/human-naive-pluripotent-stem-cells-model-x-chromosome-dampening-and-x-inactivation
#15
Anna Sahakyan, Rachel Kim, Constantinos Chronis, Shan Sabri, Giancarlo Bonora, Thorold W Theunissen, Edward Kuoy, Justin Langerman, Amander T Clark, Rudolf Jaenisch, Kathrin Plath
Naive human embryonic stem cells (hESCs) can be derived from primed hESCs or directly from blastocysts, but their X chromosome state has remained unresolved. Here, we show that the inactive X chromosome (Xi) of primed hESCs was reactivated in naive culture conditions. Like cells of the blastocyst, the resulting naive cells contained two active X chromosomes with XIST expression and chromosome-wide transcriptional dampening and initiated XIST-mediated X inactivation upon differentiation. Both establishment of and exit from the naive state (differentiation) happened via an XIST-negative XaXa intermediate...
January 5, 2017: Cell Stem Cell
https://www.readbyqxmd.com/read/27989715/human-embryonic-stem-cells-do-not-change-their-x-inactivation-status-during-differentiation
#16
Sanjeet Patel, Giancarlo Bonora, Anna Sahakyan, Rachel Kim, Constantinos Chronis, Justin Langerman, Sorel Fitz-Gibbon, Liudmilla Rubbi, Rhys J P Skelton, Reza Ardehali, Matteo Pellegrini, William E Lowry, Amander T Clark, Kathrin Plath
Applications of embryonic stem cells (ESCs) require faithful chromatin changes during differentiation, but the fate of the X chromosome state in differentiating ESCs is unclear. Female human ESC lines either carry two active X chromosomes (XaXa), an Xa and inactive X chromosome with or without XIST RNA coating (Xi(XIST+)Xa;XiXa), or an Xa and an eroded Xi (XeXa) where the Xi no longer expresses XIST RNA and has partially reactivated. Here, we established XiXa, XeXa, and XaXa ESC lines and followed their X chromosome state during differentiation...
January 3, 2017: Cell Reports
https://www.readbyqxmd.com/read/27929079/from-function-to-phenotype-impaired-dna-binding-and-clustering-correlates-with-clinical-severity-in-males-with-missense-mutations-in-mecp2
#17
Taimoor I Sheikh, Juan Ausió, Hannah Faghfoury, Josh Silver, Jane B Lane, James H Eubanks, Patrick MacLeod, Alan K Percy, John B Vincent
Mutations in the MECP2 gene cause Rett syndrome (RTT). MeCP2 binds to chromocentric DNA through its methyl CpG-binding domain (MBD) to regulate gene expression. In heterozygous females the variable phenotypic severity is modulated by non-random X-inactivation, thus making genotype-phenotype comparisons unreliable. However, genotype-phenotype correlations in males with hemizygousMECP2 mutations can provide more accurate insights in to the true biological effect of specific mutations. Here, we compared chromatin organization and binding dynamics for twelve MeCP2 missense mutations (including two novel and the five most common MBD missense RTT mutations) and identifiedacorrelation with phenotype in hemizygous males...
December 8, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27880931/an-xist-related-small-rna-regulates-kras-g-quadruplex-formation-beyond-x-inactivation
#18
Yuli C Chang, Chien-Chih Chiu, Chung-Yee Yuo, Wen-Ling Chan, Ya-Sian Chang, Wen-Hsin Chang, Shou-Mei Wu, Han-Lin Chou, Ta-Chih Liu, Chi-Yu Lu, Wen-Kuang Yang, Jan-Gowth Chang
X-inactive-specific transcript (XIST), a long non-coding RNA, is essential for the initiation of X-chromosome inactivation. However, little is known about other roles of XIST in the physiological process in eukaryotic cells. In this study, the bioinformatics approaches revealed XIST could be processed into a small non-coding RNA XPi2. The XPi2 RNA was confirmed by a northern blot assay; its expression was gender-independent, suggesting the role of XPi2 was beyond X-chromosome inactivation. The pull-down assay combined with LC-MS-MS identified two XPi2-associated proteins, nucleolin and hnRNP A1, connected to the formation of G-quadruplex...
November 17, 2016: Oncotarget
https://www.readbyqxmd.com/read/27870409/cognitive-behavioral-and-neural-consequences-of-sex-chromosome-aneuploidy
#19
REVIEW
Frida Printzlau, Jeanne Wolstencroft, David H Skuse
The X chromosome has played a critical role in the development of sexually selected characteristics for over 300 million years, and during that time it has accumulated a disproportionate number of genes concerned with mental functions. There are relatively specific effects of X-linked genes on social cognition, language, emotional regulation, visuospatial, and numerical skills. Many human X-linked genes outside the X-Y pairing pseudoautosomal regions escape X-inactivation. Dosage differences in the expression of such genes (which constitute at least 15% of the total) are likely to play an important role in male-female neural differentiation, and in cognitive deficits and behavioral characteristics, particularly in the realm of social communication, that are associated with sex chromosome aneuploidies...
January 2, 2017: Journal of Neuroscience Research
https://www.readbyqxmd.com/read/27869828/tumor-suppressor-genes-that-escape-from-x-inactivation-contribute-to-cancer-sex-bias
#20
Andrew Dunford, David M Weinstock, Virginia Savova, Steven E Schumacher, John P Cleary, Akinori Yoda, Timothy J Sullivan, Julian M Hess, Alexander A Gimelbrant, Rameen Beroukhim, Michael S Lawrence, Gad Getz, Andrew A Lane
There is a striking and unexplained male predominance across many cancer types. A subset of X-chromosome genes can escape X-inactivation, which would protect females from complete functional loss by a single mutation. To identify putative 'escape from X-inactivation tumor-suppressor' (EXITS) genes, we examined somatic alterations from >4,100 cancers across 21 tumor types for sex bias. Six of 783 non-pseudoautosomal region (PAR) X-chromosome genes (ATRX, CNKSR2, DDX3X, KDM5C, KDM6A, and MAGEC3) harbored loss-of-function mutations more frequently in males (based on a false discovery rate < 0...
January 2017: Nature Genetics
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